MINISTRY OF EDUCATION AND TRAINING HO CHI MINH UNIVERSITY OF TECHNOLOGY AND EDUCATION FACULTY OF INTERNATIONAL EDUCATION Ho Chi Minh City, March 2024 RESEARCH ON THE DURABILITY OF INJE
INTRODUCTION
THEORETICAL BASIC
Introduction of PA6 (Polyamide 6)
Polyamide 6 (PA6) is also known as Nylon 6 or polycaprolactam It is one of the most widely used polyamides globally It is synthesized by the ring-opening polymerization of caprolactam The melting point of polyamide 6 is 223°C
Figure 2.1 Molecular Structures of Polyamide 6
PA6 has high tensile strength, good impact and abrasion resistance, chemical resistance and low friction coefficient Becoming more comprehensive by adding fiberglass, changing mineral fillers and fire retardants Widely used in the automotive industry and electronic devices
Used in industrial production to produce bearings, circular gears, cams, bevel gears, rollers, pulleys, pump impellers, impellers, bevel gears, impellers, screws, nuts, Gaskets, high pressure tank gaskets, outer casings, hoses, cable jackets, pulleys, pulley sleeves, slides, solenoid valve covers, refrigeration equipment, gaskets, bearing cages, oil pipelines various on automobiles and tractors, pistons, ropes, equipment transmission belts, non-fog and daily necessities and packaging films
PA6 can be made into many different products to serve a number of fields such as textiles, garments, tire linings, etc
In garments, Nylon silk is increasingly used widely and receives more attention as it gradually replaces hand-woven fabrics with small quantities and monotonous colors Made of high-quality polymers, rich in colors, meeting user needs consumer aesthetics…
Figure 2.2 Polyamide 6 (PA6) and Application
Natural plastic masterbatch PA6 UBE 1022 MT2 is a capable engineering plastic masterbatch:
● Good heat resistance, can be cooled and reheated without losing quality like other common plastic materials
● Good resistance to organic solvents, easy cleaning, and extremely good abrasion resistance, so it can be used to replace some low-strength metals
Extremely good chemical compatibility as well as temperature resilience
● Extremely low coefficient of friction combined with mechanical properties and heat resistance, it is very effective in the production of highly worn parts such as plastic bearings
● It is not harmful to human health during use, so it is used in the food industry
● Nylon 6 is not stable in acid and base environments.
● The amide group is hydrolyzed to form amino and carboxyl.
● They are easily hydrolyzed in acidic environment; bases will form polymer chains or can be completely hydrolyzed into the monomers that make them up.
● Hydrolysis of Nylon 6 in acidic or basic media
PA plastic can be used to make gears in balanced movements, fuel filters, fuel filters, engine oil tanks, engine block covers, consumables containers, radiator water tanks
Also, them used to produce daily life products such as: plastic bags, food wrap, raincoats, fishing nets
Figure 2.4 Products of daily life
With the ability to insulate combined with high heat resistance, PA plastic is commonly used in electrical and electronic equipment in particular and the electrical industry in general Products such as vacuum cleaners, semiconductor pots, high heaters, electric gears, shells and some internal parts of electrical equipment all use this material
Due to the gyroscopic and water-absorbing properties of PA6 natural plastic beads, it affects the dimensional durability as well as the mechanical properties of the plastic beads
Plastic beads should be stored in a cool, dry environment.
The acid resistance of PA6 plastic beads is poor, so do not let it come into contact with strong acid environments
Natural plastic granules PA6 UBE 1022 MT2 have poor color fastness and low durability in polluted environments.
Introduction of Fly Ash
Fly ash (BT) is similar to coal slag, fly ash is an industrial waste product, in the form of fine particles obtained from the combustion of coal in boilers of thermal power plants, in rotary kilns of cement plants, in the blast furnace of the metallurgical plant…
The composition of fly ash usually contains silicon oxide, aluminum oxide, calcium oxide, iron oxide, magnesium oxide and sulfur oxide, and may also contain an amount of unburned coal Like other active mineral additives for concrete, fly ash is a type of artificial pozzolan, so it itself is very fine, with a particle size of 1-10 àm, an average of
Currently, fly ash is divided into two types with different characteristics
Type C coal ash (basic ash): is a product from waste dust from the burning of young peat.
Class C fly ash is typically derived from sub-bituminous coal and is primarily composed of calcium aluminum-sulfate glass, as well as quartz, tricalcium aluminate and free lime (CaO) Class C ash is also known as high-calcium fly ash because it typically contains more than 20% CaO.
Type F coal ash (acid ash): is a product from waste dust from coal combustion (coke) and is used to make high-strength concrete.
Class F fly ash is typically derived from bituminous and anthracite coal and is mainly composed of an aluminum-silicate glass, with quartz, mullite and magnetite Type F, or low calcium fly ash has less than 10% CaO.
Morphology: Fly ash is a glass sphere molecule
Density: 1.9 ~ 2.3 (Accounts for about 65% of the specific weight of cement)
Molecular size: 1.0 ~ 120/μm (Average input size: 20 ~ 30/μm
Main ingredients: SiO2, Al2O3, Fe2O3
Other properties: Pozzolan activity (Pozzolan reaction: A phenomenon that occurs when cement solidifies into concrete, a portion of free lime that remains unreacted will combine with water and the main component of Fly ash is Silica, causing a slow reaction, increasing the strength of cement after 28 days).
Good heat and sound insulation.
Significantly reduces the amount of cement used while still ensuring the requirements of concrete.
Reduces water intrusion, prevents salt and acidity.
Prevents cracking, reduces shrinkage, improves product surface and has high waterproofing properties.
Application for concrete production: increase bearing capacity, high sustainability, durability, and cool down concrete.
Low cost, not harmful to the environment.
Currently, to reduce the major impact of coal-burning furnaces on the environment as well as increase economic efficiency, coal ash has been recycled for use in many industries such as:
Construction concrete production industry: Thanks to its high activity, high smoothness and large amount of silicon oxide SiO2, when combined with cement or some other binders, it will create a type of concrete with many advantages such as: outstanding hardness, high waterproof ability
Airport and automobile road construction industry: Airport and automobile roads are projects that require high technical requirements in terms of strength, concrete compaction, ability to control heat generation to prevent cracking, etc Therefore, fly ash is a material that can meet requirements such as: increasing adhesion stability between aggregates, preventing aging for asphalt concrete
The polyamide was dried in a thermal chamber at 80 o C for 24h before processing To increase the compatibility of the polymer matrix and filler, a silane formulation was applied to the fly ash and polyamide A 20% water solution of amino silane type A 1100 was used, which is a binding agent and causes an increase in adhesion
Characteristic properties of Amino Silane A1100
Table 2.3 Specifications of gamma-aminopropyltriethoxysilane
The amino silane is an excellent adhesion promoter in acrylic coatings, adhesives and sealants With polysulfide, urethane, RTV silicones, epoxy, nitrile, phenol formaldehyde resin, adhesives and sealants, the product improves pigment dispersion and maximizes adhesion to glass, aluminum and steel
In fiberglass reinforced thermos setting plastics and thermoplastics, the amino silane enhances the flexural, tensile and interlaminar shearing strengths before and after exposure to humidity This product greatly improves wet electrical properties
Fiberglass reinforced thermoplastics, polyamides, polyesters and poly carbonates exhibit increased flexural and tensile strengths before and after wet exposure when this silane is used
Mineral Filler and Resin Systems
The amino silane maximizes the physical and electrical properties of mineral-filled phenolics, polyester resin, epoxies, polyamides, polycarbonate and a host of other thermoset and thermoplastic composites Wettability and dispersibility of filler in the polymer matrix are also improved
In shell molding, the amino silane strengthens the bond between the phenolic binder and foundry sand
The amino silane promotes an improved, water-resistant bond between the abrasive grit and phenolic resin binder
The mechanical properties of composites made of wood meal, such as impact strength,
2.3 Overview of injection molding technology
Injection molding technology is the process of injecting molten plastic to fill the cavity of the mold Once the plastic cools and solidifies in the mold, the mold is opened and the product is pushed out of the mold using a push system, during this process there is no chemical reaction
By the most common observation we can see that there are many plastic products around us From simple products such as learning tools such as rulers, pens toys to complex products such as tables, chairs, computers all are made of plastic These products come in a variety of colors and shapes, making our lives more beautiful and comfortable than This means that plastic products, largely created using injection molding technology, have become an indispensable part of our lives With properties such as: toughness, recyclability, no chemical reaction with air under normal conditions plastic materials are gradually replacing other materials such as iron, aluminum , cast iron… It is increasingly depleted in nature
2.4.1 Structuring the injection molding machine and the process of operating the machine
Injection molding machines have a general structure including the following parts:
A system that helps operate injection molding machines Includes 4 small systems:
Figure 2.10 Injection molding support system
Link systems on the machine together
Provides force to open and close the mold, creates and maintains the clamping force, causes the screw to rotate and move back and forth, forces the ejector pin and the sliding of the side core This system includes pump, motor, pipe system, oil tank…
Powering the electric motor and control system for the material storage compartment remembers the heater bands and ensures electrical safety for the machine operator with
Mechanical properties testing
Mechanical testing is a process used to determine the mechanical properties of materials It can be used to evaluate a material regardless of its shape as well as under defined geometric conditions
There are many mechanical testing methods that can be performed when evaluating materials, some of which can determine the suitability of materials for corrosion
Test methods involving impact loading, rapid loading and alternating loading are commonly referred to as dynamic testing For example, flexural impact testing, strength fatigue testing, and operating load testing of components fall under this category
Test methods in which the load is gradually increased or held constant such as static testing are known These testing methods include tensile testing, compression testing, shear testing, and hardness testing
ASTM D638 is performed by applying a tensile force to the test specimen and measuring various properties of the specimen under stress We will use a tensile force meter - under the tensile speed can be set from 1 -500 mm/min until the sample deforms (flows or breaks) The ASTM D638 standard measures many different tensile properties – however some of the properties below are the most common ASTM D638 is performed by applying a tensile force to the test specimen and measuring various properties of the specimen under stress We will use a tensile force meter - under the tensile speed can be set from 1 -500 mm/min until the sample deforms (flows or breaks) The ASTM D638 standard measures many different tensile properties – however some of the properties below are the most common
● Tensile strength: The force that can be applied to the sample before it stretches (irreversible stretching) or breaks
● Elongation (relative): is an index calculated by comparing the rate at which the material is deformed compared to its original size under the effect of a tensile force
For example: When stretching a 1-meter-long film with a constant force, the film will stretch 0.5 meters before breaking completely The elongation of the film is
[(1.5 -1.0) / 1.0] * 100 = 50% It can be understood that when this film is stretched to more than 50%, it breaks
When can ASTM D638 be applied?
There are many tensile testing methods for plastics, however the ASTMD638 standard only applies to hard plastic samples and sample thicknesses from 1 - 14 mm
If the sample is smaller than 1mm – ASTM D882 must be used to test the sample If the sample is thicker than 14mm, the sample must be rolled to less than 14 mm
Sample testing speed: Normally, the sample tensile force testing process will take from 30 seconds to 5 minutes Speed from 500 mm/min for samples with high elongation and softness 100 mm/min or less than 100 mm/min for samples with low elongation and hardness [8]
ASTM D790, like ISO 178, describes 3-point flexural tests on rigid and semi-rigid plastics as well as on long fiber-reinforced fiber composites
● Stress and strain at the yield point, maximum stress and when the sample breaks
● Tests are performed with maximum flexural tension 5%
When can ASTM D790 be applied?
Samples are produced by injection molding, or taken from sheets or panels through mechanical processing
Typically, test pieces with a cross section of 3.2 mm x 12.7 mm are used for plastic molding compounds The thickness/support ratio was determined to be 16 resulting in a support span of 51 mm
For fiber composites, a thickness/support ratio of 16 can lead to unwanted shear failure If the ratio of tensile strength to shear strength is greater than 8, larger support spans are used, with a ratio of 32, 40 or even 60 to the thickness of the sample [9]
ASTM D638 standard allows deflection to be measured through the cross-stroke display of the testing machine For more accurate measurements, it is recommended to use extensometer measure directly
The calculation of flexural stress and deformation takes into account small deflections and does not take into account friction at the supports For this reason, the method is limited to a flexural strain of 5 %
Extreme care should be taken when measuring the dimensions of the flexural test specimen Because the thickness of the sample is calculated according to the quadratic equation in flexural stress, the resulting measurement error is also a quadratic function
A measurement error of just 0.1 mm with a sample height of 3.2 mm (nominal) produces an error in flexural stress of more than 5%.
Surface inspection using SEM
2.6.1 Overview of SEM (Scanning Electron Microscope)
Scanning electron microscope SEM, also known in English as Scanning Electron Microscopy, is a famous non-destructive testing/analysis technique SEM technique uses a probe called an electron beam (electron), scanning the surface sample surface, down to nm (nanometer) resolution: [1nm -9m]
SEM scanning electron microscope creates images with large magnification (tens of thousands, hundreds of thousands of times), high resolution (nm) This capability makes the SEM Scanning Electron Microscope suitable for a wide range of scientific and industrial applications
The most outstanding advantage of the SEM linear model compared to other analysis techniques is that it allows latent variables to appear in the model
2.6.2 The history of Scanning Electron Microscope
Statistical analysis is an extremely useful tool that authors can use while conducting their research
Talking about the history of formation, people divide statistical analysis into two generations: the first generation with techniques of variance analysis, binary regression, multivariate regression and confirmatory factor analysis The second generation is the SEM linear model
In the past, when the requirements for data analysis were still not high, first- generation analysis techniques could still meet researchers' desires for expressing their work
However, with the development of computers, especially software systems, higher expectations have been set in data processing and analysis In other words, first- generation statistical analysis techniques are no longer effective
When research projects do not simply stop at analyzing data, they ask how to analyze raw data to draw conclusions and further understand behavior people (For example, customer purchasing behavior at a certain center ) That is why the SEM model was born
In the past decades, researchers have used the SEM model in many fields, including sociology (Lavee, 1988; Lorence and Mortimer, 1985), psychology, (Anderson & Gerbing ,1988; Hansell and White, 1991)
2.6.3 The operating principle and image formation in SEM
Essential components of all SEMs include:
Detector for all signals of interest
● The floor does not vibrate
● The room does not have magnetic or electric fields around
Figure 2.25 Essential Components of SEM
The source of the electrons and the electromagnetic lens is from the tungsten filament lamp placed on the top of the column and it is similar to the source of a Transmission Electron Microscope
Electrons are emitted after heat energy is applied to the electron source and move straight and gradually to the anode carrying a positive charge
The electron beam triggers the emission of high-energy scattered (Primary) electrons and low-energy secondary electrons from the specimen surface The electron beam interacts with the specimen to produce a signal that provides information about the surface topography and composition of the specimen
The sample does not require special treatment to be seen clearly under an SEM scanning electron microscope, and even air-dried samples can be directly examined However, microbial samples need to be fixed, dehydrated, and dried to maintain the structural characteristics of the cells and prevent cell collapse when exposed to the high vacuum of the microscope
The samples are mounted and coated with thin-layer heavy metal particles to allow the charges to be spatially dispersed across the surface of the sample allowing for better imaging, with high clarity
This microscopic scanning process is achieved by bouncing a beam of electrons back and forth across a thin section of the microscope When electrons reach the sample, the surface releases a small cluster of electrons called secondary electrons, which are then captured by a special detector
As the secondary electrons approach and enter the detector, they strike the photo dissipation (a luminescent material that fluoresces when hit by a charged particle or high-energy photon) This emits flashes of light that are converted into electric current by a photomultiplier, which sends a signal to the cathode ray tube This creates an image like a television picture that can be viewed and photographed
The number of secondary electrons entering the detector is largely determined by the nature of the specimen, i.e raised surfaces receive large numbers of electrons, entering the detector while exposed surfaces The concave has fewer electrons reaching the surface and therefore fewer electrons entering the detector
Therefore, raised surfaces appear brighter on the screen while depressed surfaces appear darker.
Surface inspection using DSC
2.7.1 Overview of DSC (Differential Scanning Calorimetry)
Differential scanning thermal analysis is a technique thermal commonly used in research solid, materials science, chemistry, allowing the properties to be determined phase sample temperature through measuring the heat flux radiated (or absorbed) from a sample heated in a heat stream with temperature scanning at different rates The term
"differential" refers to determining the difference between temperature (good heat)
Main applications of differential thermal scanning in the field of materials research polymers is to determine: glass transition temperature, melting temperature, crystallization temperature; decomposition heat, induction heat; kinetic parameters of chemical reactions; curing process; temperature degradation
DSC differential scanning thermal analysis equipment can be applied in research and
2.7.2 The history of Differential Scanning Calorimetry
This technique was first invented by E.S Watson and M.J O'Neill (Perkin Elmer Corp), and was introduced commercially for the first time at the Conference on Analytical Chemistry and Applied Spectroscopy in Pittsburgh (USA) in 1963 In 1964, the technique was further refined with improved adiabatic differential scanning calorimetry invented by P.L Privalov and D.R Monaselidze
2.7.3 The operating principle of DSC
DSC works based on the principle of change temperature and heat emitted from the sample when heated and compared with information from the standard sample The sample chamber consists of two weighing pans, one standard weighing pan containing no sample and made of material with standardized thermal information The remaining weighing pan contains the sample to be analyzed The disc is placed on a micro-balance system allowing for accurate weighing mass sample, along with a temperature sensor system placed below the weighing pan allows determining the temperature of the sample This entire system is placed in a combustion chamber where the heating rate is often changed by blowing air streams From the Sensor measurement, the heat flux from the sample will be determined as a function of temperature
H is enthalpy hidden heat, 𝐶 𝑃 is the specific heat of the sample (𝐶 𝑃 = 𝐶 𝑚) with:
C is the specific heat, m is the mass, 𝑓(𝑇, 𝑡) is a function of temperature and time
Besides measuring heat flow, the DSC device can measure mass changes thanks to the micro-balance placed below the balance pan, and can perform the thermogravimetric analysis (Thermal gravimetric analysis - TGA)
Figure 2.26 An example of a DSC measurement curve with a temperature-dependent heat flow.
EXPERIMENTAL AND SELECTION PROCESS
Process of forming test specimens
Step 1: Divide the resin evenly among the 4 given cases using a magnetic scale
Step 2: Dry the plastic in an oven for 9 hours at a temperature of 110, stir the plastic once every 30 minutes
Divide the fly ash ratio according to the 4 given cases:
Dry the fly ash in an oven for 6 hours at a temperature of 110, stir the ash once every
- Step 1: Prepare 20% pure silane solution with 2% filler content according to the following ratio:
- Step 2: Magnetically stir the prepared mixture for 10 minutes
- Step 3: Add Acetic Acid solution and continue magnetic stirring until red litmus turns the solution pH to 4 or 5
Note: Because silane hydrolysis rapidly and cannot be stored for a long time, this solution must be used within one hour of preparation
3.1.4 Mix Plastic + fly ash + additives
Mix the dried plastic with the solution you just mixed with a mixer for 1 hour with
250 degrees of heat to disperse the fly ash evenly Spray the additive solution directly into the mixing tank and continue stirring well
Note: Based on the fly ash ratio in each case, mix the corresponding solution ratio
Step 1: Start the machine and adjust the temperature
Step 2: Pour plastic into the hopper, start pulling
Step 3: Align the end of the plastic fiber to the appropriate fiber extrude
Figure 3.6 Dashboard of injection molding machine
Experiment process
The process of injection molding for sample extraction
The type of plastic injection machine used by Haiti International is Mars III series Specifically, the plastic injection machine used is Haiti International MA Model 1200III
The type of plastic used to make the mold is 100% PA6, glass fiber PA6+2.5% Fly ash, PA6 +5% Fly ash, PA6 + 7.5% Fly ash
The plastic molding process goes through many stages and teams rely on the
First, test casting is performed to determine the set of parameters that yield the results, lowest value, ensuring the sample can be molded properly, i.e., without resin shortages or common molding defects such as burrs or flashes
After getting the smallest set of parameters, we proceed to set the values at 3 levels as follows
Based on the above data, we find three different values at three different levels
After conducting molding tests with PA6 + 2.5% fly ash, the team was determining the following parameters
Table 3.2.1 The minimum value table for the parameter set of PA6 + 2,5% Fly Ash at normal temperature
Based on the data above, a table was created with three values and four levels as follows.
Parameters Level 1 Level 2 Level 3 Level 4
Table 3.2.2 Four levels of utilization in the univariate table
Table 3.2.3 Univariate value table for all case
We obtained 16 cases, each with 4 different parameter values
The sampling process is conducted with the following quantities:
● Step 1: Pour each case's resin into the hopper
● Step 2: Adjust the temperature according to the variable table, wait for the temperature to stabilize
● Step 3: Proceed with plastic injection, remove the first 3 samples of each case to stabilize the plastic
For each case in the univariate table, 5 samples were taken Total number of samples above 160 samples completed (80 tensile samples, 80 flexural samples)
Note: Each time you move to the next case, you must remove all the old plastic in the hopper
ANNALYSIS AND EVALUATION OF THE RESULTS
Shore D Hardness test
The Shore D hardness scale is a popular test method to determine how hard different materials are This scale is a crucial tool in sectors like manufacturing, construction, and the automotive industry, where hardness is a key factor in product development, quality assurance, and material selection The Shore D hardness rating is determined by how far an indenter can go into a material when a specified force is applied This scale is specifically used to gauge the toughness of semi-rigid plastics, hard rubber, and hard plastics It is noteworthy that the indenter on the Shore D testing device generates a 10- pound spring force
The Shore D hardness scale system is valuable because it’s quick, non-destructive, easily repeatable, and suitable for thin or small samples The Shore D hardness scale's drawbacks, however, include its sensitivity to surface finishing, and surface preparation
The purpose behind the Shore D hardness scale, also known as the durometer scale, is to measure and compare the hardness values of materials such as plastics, rubbers, and elastomers The results indicate how much force it takes to put an indentation into a given material Higher numbers indicate greater hardness on the scale, which runs from 0 to 100 The Shore D scale is frequently used in sectors like construction and manufacturing to give designers an idea of the product’s quality and potential longevity
4.1.2 Type of materials can be tested
The materials that can be tested include thermoplastic elastomers, other hard rubbers, and rigid plastics A diamond-tipped indenter's penetration depth is measured using the Shore D hardness scale to determine the material's hardness This scale is especially helpful for testing materials that need to be highly rigid, such as automotive, athletic, and industrial components
In an industrial setting, hard plastics, rubbers, and other materials are measured using the Shore D hardness scale The Shore D scale utilizes a durometer to gauge how deeply a pointed object can pierce a material under a known, constant force The material's hardness is then calculated using this depth measurement
The following are some advantages of conducting material testing using the Shore D hardness scale:
● High Precision: A material's hardness can be precisely measured using the Shore
D hardness scale, enabling accurate comparisons between various materials
● Wide Range of Applications: Numerous materials, including plastics, rubber, and composites, can be tested for hardness using the Shore D hardness scale
● Quick and Easy: A Shore D hardness tester is a quick and simple tool found in many industries to determine a material's hardness
● Portable: Materials can be tested on-site since Shore D hardness testers are portable
● Non-destructive: The Shore D hardness test is non-destructive, in contrast to other methods of material testing, so test articles can continue to be used afterward
The Shore D hardness scale has some drawbacks, such as [10]:
● Limited Range: The 0-100 range of the Shore D scale is not adequate for all materials
● Material Dependency: Comparing hardness values between different materials can be challenging because different materials may respond differently to the same Shore D scale measurement
● Surface Effects: A material’s surface finish can cause inconsistencies in Shore D measurements
● Temperature Sensitivity: Temperature can have an impact on some materials' hardness, so it is important to compare hardness values measured under consistent temperatures
● Operator Error: Shore D hardness measurements must be performed with precision, so the equipment needs careful calibration and operator skill
4.1.5 XF Shore D Plastic and Rubber Hardness Tester
After pressing the product, we test the flexural and tensile strength of the product on a tensile machine at the Institute of Technical Education in Ho Chi Minh City
Filing press (bar) Packing press (bar) Melt temperature ( o C) Shore D Hardness
Check the tensile and flexural strength of the product
After pressing the product, we test the flexural and tensile strength of the product on a tensile machine at the Institute of Technical Education in Ho Chi Minh City
Figure 4.2 Plastic tensile and bending machine
Steps using plastic tensile and flexural machine
● Turn on CB inside the electrical cabinet
● Connect the cable to the personal computer
Step 1: Select number 1 to turn the machine ON
Step 2: Select numbers 2 and 3 to set the force and displacement values to 0
Step 3: Enter number 11 to select pulling speed (maximum 10,000)
Step 4: Select number 4 (Jog Up) or select number 5 (Jog Down) to move to the pull sample position
Step 5: After setting the pattern, select number 6 (Set Home)
Step 6: Select number 4 (Jog Up) to break the sample, let the machine run about 10 mm more and select number 7 (Set End)
Step 7: Choose number 8 (Go Home)
Step 8: Choose number 9 (Create new file)
Step 9: Select number 10 (Go end) to drag and get data
4.2.1 Check the tensile strength of the product
Proceed to place the plastic in the tensile position
Figure 4.4 Position of tensile plastic
After jigging the sample, press Jog up to pull the sample
A Experimental results chart of tensile strength
Figure 4.5 Tensile stress chart of PA6 + 0% Fly Ash
Figure 4.6 Tensile stress chart of PA6 + 2.5% Fly Ash
Figure 4.7 Tensile stress chart of PA6 + 5% Fly Ash
Figure 4.8 Tensile stress chart of PA6 + 7.5% Fly Ash
B Experimental chart comparing each fly ash percentage
Figure 4.9 Chart of influence of fly ash content on the durability of plastic
The first chart gives information about the influence of fly ash content on the durability of PA6 As the fly ash content increase, the durability of plastic drop At 0% fly ash content, the UTS reached at 14.64 MPa The durability of plastic is 12.9 MPa decreasing to 1.74 MPa when the fly ash content is 2.5% Then, at a level of 5% fly ash content, the UTS go up at 13.31 MPa But at 7.5% fly ash content, the durability continues to decrease to 11.44 MPa
In the above experiment, it was shown that the effect of changing ash content on the tensile strength of the material is insignificant at concentrations from 2.5% to 5%
Thereby it can be explained that the strongest impact of fly ash content on the tensile stress of the complex is below 5% (7.5%)
Figure 4.10 Chart of influence of fly ash content on plastic elongation
The second chart illustrating the influence of fly ash content on the elongation of PA6
As the fly ash content increases, the elongation of PA6 decreases When the fly ash content is 0%, the average elongation is 3332.99 MPa Then, at a level of 2.5% fly ash content, the elongation reaches 315.32 MPa The elongation of PA6 is 250.1 MPa, decreasing to 184.78 MPa when the fly ash content is 5% At 7.5% fly ash content, the average elongation continues to decrease to 102.62 MPa
When changing the fly ash content, the mechanical properties of the material also change in many different trends Regarding the elasticity of the material, when increasing the fly ash content from 0% to 7.5%, the elongation of the complex gradually decreases This can be explained because when the filler content is increased, the bonds of the plastic are hindered by fly ash particles, causing the bonds in the complex to break more easily than in pure plastic
Figure 4.11 Chart of influence of fly ash content on Elastic Modulus
The third chart show the influence of fly ash content on Elastic Modulus At 0% fly ash content, the Elastic Modulus is 345,92 MPa There is a increase in elastic Modulus at 2,5% percentage with 354,6 MPa Then, elastic modulus continues to decrease to 337,47 MPa at 5% of fly ash content The Elastic Modulus finally reach the top with elastic Modulus at 355.67MPa
When the material reaches the threshold of fly ash content of 7.5%, the elastic modulus compared to tensile stress reaches the highest threshold in experimental samples Besides, we can also see that the elastic modulus of plastic combined with 2.5% fly ash gives equivalent results This proves that the ash content of 2.5% and 7.5% is both the content that allows the material to withstand the greatest impact when compared to each other and 354.6 MPa; 335.67 MPa is the highest deformation level achieved by this complex
Conclusion: After three experimental surveys of fly ash content to mechanical properties of PA6 material, the following conclusions were drawn:
● The fly ash content range has a strong impact on material expansion from 2.5% to 7.5%
● Tensile stress does not depend on fly ash content from 5% to 7.5%
● Fly ash content affects materials that are less susceptible to tensile deformation: 2.5% and 7.5%
Through experiments, it has been shown that the most optimal fly ash content that meets the criteria for being optimal when passing tensile testing is 2.5% fly ash
4.2.2 Check the flexural strength of the product
Proceed to place the plastic in the flexural position
Figure 4.12 Position of bending plastic
After jigging the sample, press Jog up to pull the sample
A Experimental results chart of flexural strength
Figure 4.13 Flexural strength chart of PA6 + 0% Fly Ash
Figure 4.14 Flexural strength chart of PA6 + 2.5% Fly Ash
Figure 4.15 Flexural strength chart of PA6 + 5% Fly Ash
B Experimental chart comparing each fly ash percentage
Figure 4.17 The charts compare the results of bending testing
The first chart shows the influence of fly ash content on the flexural strength of plastic Overall, the FS (MPa) experienced an increase with the fly ash content ranging from 0% to 5%, followed by a slight decline in FS (MPa) towards the end of the period at 7.5% fly ash content At 0% fly ash content, the UTS is 10.95 MPa, which then reached 11.49 MPa at a fly ash content of 2.5% The UTS was highest at 5% fly ash content, measuring approximately 12.14% Finally, the strength of the plastic slightly decreased to 11.31 MPa at a fly ash content of 7.5%
Experiments show that the resistance of the material tends to increase gradually from 0% to 5% At 7.5%, although the data tends to decrease, it is not significant This can be explained by the existence of fly ash mixed with the base plastic, which will combine the two inherent mechanical properties of the two basic materials: the flexibility of the plastic and the smoothness of the ash, so the material The material will be subjected to increasingly variable loads as the fly ash content increases
Figure 4.18 Chart of influence of fly ash content on the deformation plastic The second chart gives information about the influence of fly ash content on the deformation of plastic The higher the level of fly ash, the lower the deformation of PA6 plastic At 0% fly ash, the deformation of PA6 plastic is 38.4 MPa When the fly ash content is increased to 2.5% and 5%, the elongation decreases by 0.03 MPa, reaching 38.37 MPa The deformation of PA6 plastic continues to decrease to 38.35 MPa when the volatile content is 7.5%
The above experiment shows that the effect of changing ash content on the deformation of the material is insignificant However, the influence of fly ash content on material deformation occurs with a decreasing trend from 0% to 7.5% This can be explained because the bond of the base material (PA6 plastic) tends to decrease gradually when the fly ash content is increased, then the ash particles will interfere with the bonds as a material The material becomes brittle and breaks more easily when subjected to direct impact from flexural flow
Figure 4.19 Chart of influence of fly ash content on Elastic Modulus
A chart illustrates the influence of fly ash content on elastic modulus As the fly ash content increases, the elastic modulus increases When the fly ash content is 0%, the elasticity is 1657.83 MPa Then, at a level of 2.5% fly ash content, the elastic modulus reaches 1878.28 MPa Next, at a level of 5% fly ash content, the elasticity continues to increase to 1874.61 MPa, after which it reaches the peak at 2031.74 MPa when the fly ash content is 7.5%.
Through experiments, it has been shown that the strength of the material will gradually change when increasing the amount of filler, specifically from 0% to 7.5% This can be explained by the nature of the filler, which is fly ash, which has good plasticity and durability, so when combined with a base of PA6 plastic, it will create a complex with high specific hardness in elastic modulus experiments The highest flexural modulus is 2031.74 MPa, nearly 1,2 times higher than the optimal flexural modulus of PA6 plastic.
Conclusion: After three experimental surveys of fly ash content to mechanical properties of PA6 material, the following conclusions were drawn:
+ Flexural stress gradually decreases insignificantly when fly ash content is from 0% to 7.5%
+ Ash content has a strong impact on the deformation of the material
+ Fly ash content affects the material with little flexural deformation of 7.5%
Through experiments, it has been shown that the most optimal wood pulp content that meets the criteria for being optimal when passing flexural tests is 7.5% fly ash
SEM analysis
Figure 4.22 PA6 + 5% fly ash plastic structure
Figure 4.23 PA6 + 7.5% fly ash plastic structure The four images clearly show the structure of PA6 PA6, being a flexible material, appears smoother compared to PA6 with 2.5%; 5%; 7.5% Fly ash Therefore, we can observe that the elongation of pure PA6 (0%) is approximately 3 times higher than that of PA6 with 7.5% Fly ash, when compared with 2.5% Fly ash, the elongation of pure times higher All cases with an additional percentage of fly ash have same the deformation when and are equal to the case of pure PA6 On the other hand, the higher the percentage of fly ash added to PA6, the higher the durability and brittleness
Measurement results show that the fly ash content varies quite a lot, but the distribution of ash on the plastic base in the presence of Amino silane is very uniform, showing good compatibility between the base material + filler + additives.
DSC analysis
Figure 4.24 DSC analysis PA6 + 0% Fly Ash The image above is the DSC result generated on the membrane sample Polycaprolactam The heat treatment factors are determined as follows:
● The melting temperature is determined :67.35 J/g
Heating rate is an important characteristic of thermoplastics because it is related
DHm: the melting temperature due to DSC
DHmo: the reference for heat of fusion
For Polycaprolactam, this reference value is 223 J/g This gives an estimated percent crystallize of 30.2% for the film Polycaprolactam receive.
Figure 4.25 DSC analysis PA6 + 2.5% Fly Ash The image above is the DSC result generated on the membrane sample Polycaprolactam The heat treatment factors are determined as follows:
● The melting temperature is determined :69.01 J/g
Heating rate is an important characteristic of thermoplastics because it is related to the percentage of crystallization of the material.
DHm: the melting temperature due to DSC
DHmo: the reference for heat of fusion
For Polycaprolactam, this reference value is 223 J/g This gives an estimated percent crystallize of 30.9% for the film Polycaprolactam receive
Figure 4.26 DSC analysis PA6 +5% Fly Ash The image above is the DSC result generated on the membrane sample Polycaprolactam The heat treatment factors are determined as follows:
● The melting temperature is determined :68.95 J/g
Heating rate is an important characteristic of thermoplastics because it is related to
DHm: the melting temperature due to DSC
DHmo: the reference for heat of fusion
For Polycaprolactam, this reference value is 223 J/g This gives an estimated percent crystallize of 30.92% for the film Polycaprolactam receive.
Figure 4.27 DSC analysis PA6 +7.5% Fly Ash
The image above is the DSC result generated on the membrane sample Polycaprolactam The heat treatment factors are determined as follows:
● The melting temperature is determined :57.82 J/g
Heating rate is an important characteristic of thermoplastics because it is related to the percentage of crystallization of the material
We have the formula to determine it as follows:
DHm: the melting temperature due to DSC
DHmo: the reference for heat of fusion
For Polycaprolactam, this reference value is 223 J/g This gives an estimated percent crystallize of 25.93% for the film Polycaprolactam receive.
Figure 4.28 Percentage crystallization chart Overall, the curves of all obtained cases show the crystallization phase transition process Glass transition temperature of 4 case start at about 0.3 W/g Except for the 7.5% case, the remaining cases all have upward curves The starting temperature is also relatively similar at about 212 degrees, the more the fly ash ratio increases, the smaller the crystallization peak temperature At case PA6 + 0% Fly Ash, the area reached at 67.53 J/g Then, the area of DSC analysis is 69.01 J/g when PA6 + 2.5% Fly Ash There
Optimization process
Using the Taguchi analysis method, the following observations are made:
A Output results of tensile strength
UTS = -2.3 - 0.214 Fly Ash Content + 0.046 Filling pressure + 0.087 Packing pressure
Term Coef SE Coef T-Value P-Value VIF
S R-sq R-sq(adj) R-sq(pred)
Source DF Adj SS Adj MS F-Value P-Value
Level Fly Ash Content Filling pressure Packing pressure Melt temperature
Figure 4.30 The main component affects the composite
Figure 4.31 Graph representing SN ratio
Fly Ash Content Filling pressure Packing pressure Melt temperature
B Output results of Flexural strength
FS = 9.18 + 0.1011 Fly Ash Content + 0.0237 Filling pressure - 0.0115 Packing pressure + 0.0071 Melt temperature
Term Coef SE Coef T-Value P-Value VIF
S R-sq R-sq(adj) R-sq(pred)
Source DF Adj SS Adj MS F-Value P-Value
Level Fly Ash Content Filling pressure Packing pressure Melt temperature
Figure 4.32 The main component affects the composite
Figure 4.33 Graph representing SN ratio
Fly Ash Content Filling pressure Packing pressure Melt temperature
- Fly ash content has the greatest impact on tensile strength results, and the least impact on tensile strength is filling pressure
- The most appropriate pressing plan is:
- Fly ash content has the greatest influence on flexural strength results, and the least influence on flexural strength ispacking pressure
- The most appropriate pressing plan is:
CONCLUSION AND RECOMMENDATION
Conclusion
Our research team has completed an excellent scientific research task, with a report written very professionally in both form and content Our research has succeeded in solving the following important problems:
● Multidisciplinary knowledge combination: We have successfully applied knowledge from many different fields such as mathematics, engineering, science and technology and social sciences to study the impact of materials on durability durability of composite products
● Analysis and evaluation: We performed a comprehensive analysis and evaluated the research results accurately and thoroughly Comparing and charting the process of processing tensile and flexural strength measurement results has helped us present the results in a clear and easy-to-understand manner
● Dealing with practical constraints: We coped with practical constraints and met the requirements effectively The sampling process during the plastic injection molding process and tensile and flexural strength testing were carried out thoroughly and accurately, showing care and professionalism
● Effective use of technical tools: We have demonstrated our understanding and proficiency in using technical tools during the operation of plastic injection machines and tensile testing machines
● Objective comments and evaluation: We have provided objective comments and evaluation of SEM (electron scanning) and DSC (pyrolysis spectroscopy) images
● Optimization using artificial neural networks (ANN): We have developed optimization using artificial neural networks (ANN).
Recommendation
My team has achieved commendable achievements in the research process on the influence of materials on the durability of Composite products The main problems have evaluation and comments At the same time, the application and use of technical tools and professional understanding were demonstrated during the research process
This research brings potential benefits in application and expansion to other fields Below are expanded development directions that other groups can pursue:
● Expand the scope of research on materials: Continue to explore the effects of different materials on the durability of composite products Research on new, recycled or synthetic materials can be performed to evaluate their mechanical properties and durability
● Optimize composite formulation: Focus on optimizing composite formulation to achieve maximum strength of composite products Vary the proportions and types of materials, layer structures, and manufacturing processes to find the ideal combination of strength and other mechanical properties of the composite product
● Application and field expansion: Apply research results to many different industrial fields Continue research on the application of composite materials in industries such as automobiles, aerospace, construction, shipbuilding and renewable energy This will create new development opportunities for composite applications
● Research and expand development directions: Continuing to research and expand the mentioned development directions, your graduation thesis will contribute to the understanding of the influence of materials on product strength composite after injection molding This will bring practical value in the field of composite manufacturing and applications
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Figure 1.a Location of breakage Figure 1.b Location of breakage
Figure 1.c Location of breakage Figure 1.d Location of breakage