PHÂN TÍCH POLYME (POLYMER ANALYSIS) pdf

TRƯỜNG ĐẠI HỌC BÁCH KHOA ĐÀNẴNG KHOA HOÁ PHÂN TÍCH POLYME (POLYMER ANALYSIS) TS. ĐoànThị Thu Loan ♣♣♣ üIs a branch of polymer science dealing with analysis and characterisation of polymers. üThe complication of macromolecular chains, the dispersion in molecular weight, tacticity, crystallinity, orientation, composition of polymers etc. and complex morphological systems ⇒ analysis of polymer ≠ the small organic materials ⇒ Focus on viscoelasticproperties, dynamic mechanical testing. Polymer analysis •Instronmechanical tester •Vickerhardness tester •DMA •Melt flow indexer •Torsions Rheometer • •-AFM, SEM •-FT-IR •-Pull-out test Instruments •FT-IR •IR-microscope •GPC ( size exclusion chromatography SEC) •-Viscosimetry •-X-ray (WAXS and SAXS) •-EM, SEM, TEM, AFM •-Dynamic and static methods for contact angle measurements. -Tensile, flexural, impact, compression, hardness tests, -Rheologicaland viscoelastic properties, stiffness and modulus, surface tension, permeation and diffusion in polymers, adhesion tests, density -Surface roughness, -Chemical composition, -Interface characetrisation -Molecular weight determination, -Microstructuralcharacterisation and compositional analysis, -Crystallinity, -Investigation of polymer morphology, particle size, -Contact angle and wettability measurements Mechanical and Physical Properties Surface Characterisation Chemical, Molecular and Structural Characterisation Methods of polymer analysis •GC •pH meter •HPLC •Karl-Fischer titration •Thermogravimetricanalyser (TGA) •TGA-FTIR coupled technique •Differential scanning calorimetry(DSC) •Modulated differential scanning calorimetry(ADSC) •Dynamic thermomechanicalanalyser (DMTA) •Dielectric relaxation Instruments Inolabconductivity meter • Purity and molecular weight of small molecules, water content in organic solvents, surface tension measurement, pH -Melting point, glass transition temperature, free rotation temperature, -Degradation and stability behaviour of polymers Conductivity, electric current in solution, light emitting and electromagnetic properties Miscellaneous (hontap)Thermal Behaviour Electrical and Optical Properties Methods of polymer analysis -For quality control -For predicting service performance -To generate design data -To investigate failures Purpose of polymer analysis Essential to identify the purpose of testing, because the requirements for each of the purposes are different. -Precision -Reproducibility -Rapidity Balance of these attributes, according to the purpose of the test -Complexity -Automated test -Nondestructive test -Cost üNondestructive methods are advantageous and indeed essential when 100% of the output is being tested. üThe tests should be simple and inexpensive, and automation will probably aid the rapidity of testing. üTests related to product performance are preferred. Quality Control Tests üThe most important factor is that the tests relate to service conditions and to aspects of product performance. üshould not be too complex, although rapidity and cheapness are less important than was the case with quality control. üNondestructive tests are not always appropriate when predicting product performance, as it may be necessary to establish the point at which failure occurs. Tests Predicting Product Performance üUsually test pieces are of a simple shape and a specified size, whereas the product may be of a different geometry and size üData must be presented in a form that enables the designer to allow for changes in geometry, time scale, etc which implies detailed and comprehensive understanding of material behavior üIt follows that data of this type are expensive to produce and that results are unlikely to be obtained with great rapidity. üHowever, automation may be advantageous, particularly in the case of tests running for a long time (creep tests) Tests for Producing Design Data üSome understanding of the various mechanisms of failure is necessary before suitable tests can be chosen. ü Tests need not be complex but must be relevant Ex: a simple measurement of product thickness may establish thatthere has been a departure from the specified design thickness. üThe absolute accuracy of the test may not be important, but it is essential that it be capable of discriminating between the good and the bad product. Tests for Investigating Failures What are our expectations of polymer materials? •Excellent Characteristics: Mechanical and Physical Properties Thermal Behaviour Surface and interface Characteristics Electrical and Optical Properties •Safe to use •Light weight •Reliable, durable •Low cost •Less adverse environmental impact •Good resistance to environmental attacks [...]... Original cross-sectional area Stress-train behavior of polymers Stress –Strain Behavior Stress –Strain Behavior üModuli of elasticity for polymers are ~ 10MPa-4GPa (compare to metals ~ 50 400 GPa) üTensile strengths are ~ 10 -100MPa (compare to metals, hundreds of MPa to several GPa) üElongation can be up to 1000 % in some cases (< 100% for metals) üPolymers are also very sensitive to the rate of deformation... sensitive to the rate of deformation (strain rate) Decreasing rate of deformation has the same effect as increasing T TENSILE RESPONSE: ELASTOMER CASE Deformation of Amorphous Polymers Deformation of Semicrystalline and crosslinked Polymers Stress-strain curves Flexural test Scope: üMeasures the force required to bend a beam under 3 point loading conditions üThe data is often used to select materials for... Mechanical Testing of Polymers Types of Mechnical Tests (h) (i) Tensile test (a) Compression test (b) Flexural test (d) (e) (f) Shear (g) Impact test (h) (i) Tensile test Scope: üMeasure the force required to break a specimen . BÁCH KHOA ĐÀNẴNG KHOA HOÁ PHÂN TÍCH POLYME (POLYMER ANALYSIS) TS. ĐoànThị Thu Loan ♣♣♣ üIs a branch of polymer science dealing with analysis and characterisation of polymers. üThe complication. composition of polymers etc. and complex morphological systems ⇒ analysis of polymer ≠ the small organic materials ⇒ Focus on viscoelasticproperties, dynamic mechanical testing. Polymer analysis •Instronmechanical. polymers Conductivity, electric current in solution, light emitting and electromagnetic properties Miscellaneous (hontap)Thermal Behaviour Electrical and Optical Properties Methods of polymer