DSpace at VNU: Enhanced mechanical and thermal properties of recycled ABS nitrile rubber nanofil N15 nanocomposites

DSpace at VNU: Enhanced mechanical and thermal properties of recycled ABS nitrile rubber nanofil N15 nanocomposites tài...

Accepted Manuscript Enhanced Mechanical and Thermal Properties of Recycled ABS/Nitrile Rubber/ Nanofil N15 Nanocomposites Nguyen Dang Mao, Tran Duy Thanh, Nguyen Thi Thuong, Anne-Cécile Grillet, Nam Hoon Kim, Joong Hee Lee, Prof PII: S1359-8368(16)30063-4 DOI: 10.1016/j.compositesb.2016.03.039 Reference: JCOMB 4140 To appear in: Composites Part B Received Date: 27 November 2015 Revised Date: 25 January 2016 Accepted Date: 13 March 2016 Please cite this article as: Mao ND, Thanh TD, Thuong NT, Grillet A-C, Kim NH, Lee JH, Enhanced Mechanical and Thermal Properties of Recycled ABS/Nitrile Rubber/Nanofil N15 Nanocomposites, Composites Part B (2016), doi: 10.1016/j.compositesb.2016.03.039 This is a PDF file of an unedited manuscript that has been accepted for publication As a service to our customers we are providing this early version of the manuscript The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain ACCEPTED MANUSCRIPT Enhanced Mechanical and Thermal Properties of Recycled ABS/Nitrile Rubber/Nanofil N15 Nanocomposites Nguyen Dang Mao, a Tran Duy Thanh, a,b Nguyen Thi Thuong,c Anne-Cécile Grillet,d Nam a Department of Polymer Composites, Faculty of Material Science, University of Sciences, Vietnam National University, Ho Chi Minh City, Viet Nam Advanced Materials Institute of BIN Technology (BK21 Plus Global) & Department of BIN SC b RI PT Hoon Kim, b Joong Hee Leeb,e* Korea M AN U Convergence Technology, Chonbuk National University, Jeonju, Jeonbuk, 54896, Republic of c Hi-Tech Institute, Nguyen Tat Thanh University, Ho Chi Minh City, Viet Nam d LOCIE, Polytech Annecy-Chambery, Université de Savoie, Campus Scientifique, 73376 Le Bourget du Lac Cedex, France e TE D Carbon Composite Research Center & Department of Polymer-Nano Science and AC C EP Technology, Chonbuk National University, Jeonju, Jeonbuk, 54896, Republic of Korea *Corresponding author Tel.: 82-63-270-2342; Fax: 82-63-270-2341 E-mail address: jhl@chonbuk.ac.kr (Prof Joong Hee Lee) ACCEPTED MANUSCRIPT Abstract: Hybrid materials based on recycled acrylonitrile butadiene styrene (re-ABS) and nitrile rubber (NBR) upgraded by montmorrilonite nanofil 15 (N15) were prepared by melt processing The morphology and structure of the nanocomposites were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and transmission electron RI PT microscopy (TEM) analyses As revealed by SEM, NBR and N15 were homogeneously dispersed in the re-ABS matrix The XRD and TEM studies demonstrated that N15 was mainly located in the re-ABS matrix in the form of an intercalated-exfoliated mixed structure that led to SC an increase of the melting viscosity of the materials The mechanical properties of the nanocomposites showed a good balance when adding phr (parts per hundred parts of resin) of M AN U N15 into the re-ABS/NBR (90/10) blend Furthermore, the thermal stability of the nanocomposites was also improved in the presence of NBR and N15 AC C EP properties; E Recycling TE D Keywords: A Polymer-matrix composites (PMCs); B Mechanical properties; B Thermal ACCEPTED MANUSCRIPT Introduction Acrylonitrile butadiene styrene (ABS) is a widely used engineering thermoplastic for industrial and domestic appliances due to its numerous excellent properties including mechanical properties, dimensional stability, and chemical resistance performance [1] A large RI PT amount of recycled ABS (re-ABS) is discarded every year creating major economic and environmental issues [2] In order to address this issue, several different methods including burial, combustion, and recycling have been utilized Among these approaches, recycling ABS SC brings great benefits to the economy as well as reducing environmental pollution problems The main limitation of re-ABS is that its properties are usually worse compared to the virgin M AN U material During melt reprocessing, partial degradation of the rubber part connected to voids in the re-ABS [3, 4] leads to a reduction of the impact strength and strength [4, 5] Blending of immiscible thermoplastics is a traditional tool to balance mechanical parameters, mostly to improve the toughness Various efforts have been focused on the blending of the ABS TE D with soft polymers and elastomers [6-9] Among various usable elastomers, acrylonitrile butadiene rubber (NBR) as known as nitrile rubber has gained much interest because it not only enhances toughness of polymers effectively but also provides required properties for specific EP applications NBR has been also successfully utilized to yield novel polymeric blends with high performance of chemical resistance [10] and to improve flame retardancy [11] due to the AC C presence of the polar groups on structure However, in order to obtain good behavior of polymer blending, some crucial parameters, such as phase separation, interfacial adhesion, and physical and chemical interactions should be considered The properties can be improved by the addition of compatibilizers, which effectively enhances the interfacial adhesion of blends [12-14] In most cases with and without compatibility components, blending also results in a reduction of the modulus value of the ACCEPTED MANUSCRIPT material systems So far, the development of the new polymer materials with simultaneous increase of strength, modulus, and toughness for enhanced applications is really necessary The use of nanofillers as reinforcements in polymer systems has attracted significant attention in academic and industrial fields [15-22] The high performance of polymer RI PT nanocomposites is based on the high mechanical parameters and aspect ratios of nanofillers at a very low content In addition, many studies indicated that compatibilization of the polymer blend components can be achieved by the incorporation of nanofillers due to decreasing the SC total free energy of mixing [23, 24] The dispersion status and localization of nanofillers are predominant factors that affect the enhancement of properties of the polymer blend Depending M AN U on the affinity between the nanofillers with the matrix and minor phase, nanofillers could preferably locate in the matrix [25-28], in the minor phase [28], or exist at the interfacial region [29, 30] It appears that the best balance of mechanical properties (stiffness and toughness) results from well-dispersed nanofillers throughout both the matrix and interfacial region TE D [31-33] Clays are really environmentally friendly, readily available in large quantities, low-cost, and exceptional mechanical properties of each individual layer compared to conventional fillers EP [34] The enhancement of the clay-filled polymer is achieved by breaking down clay particle aggregates into individual nanolayer with nm thickness and 200 nm lateral dimensions at AC C very low content [34] Furthermore, the functional groups attached on the clay surfaces act as effective sites to improve compatibility between clay and polymer [29-33] Therefore, clay has attracted increasing interests for polymer nanocomposites both in academia and industry during last decade In this work, the first attempt to re-use re-ABS was carried out by combining re-ABS with nitrile butadiene rubber (NBR) and montmorrilonnite nanofil 15 (N15) Although a numerous ACCEPTED MANUSCRIPT reports about nanocomposites with ABS have been published, to the best of our knowledge, no report is available on the thermal and mechanical behavior of re-ABS/NBR blends elaborated with N15 The main aim of this work was to study the effects of N15 and NBR on the morphology and properties of re-ABS to obtain satisfactorily balanced mechanical parameters RI PT of the hybrid material Since the virgin ABS is expensive, these nanocomposites become economically attractive and thus they can be extensively used for the applications required for SC high mechanical properties and low material cost Experimental methods M AN U 2.1 Materials Recycled ABS (re-ABS) pellets (density of 1.05 g/cm3) from electronic equipment were supplied by Nhua Tai Sinh Co., Ltd (Vietnam) The nitrile-butadien rubber (KNB 35L), a cold emulsion copolymer of acrylonitrile and butadiene (density of 0.98 g/cm3 and 34 wt% bound TE D acrylonitrile), was provided by Kumho Petrochemical Co., Ltd (Korea) Nanofil 15 (N15), a distearyldimethylammonium chloride exchanged montmorrilonite with an average grain size of 25 µm, was provided by Sued-Chemie AG Co (Germany) Photograph of the samples and EP chemical structures of the re-ABS, NBR and nanofil N15 are shown in Fig.1 AC C 2.2 Preparation of re-ABS, re-ABS/NBR, and re-ABS/NBR/N15 Prior to processing, re-ABS was dried at 80°C for 48 hours The samples of re-ABS, re-ABS/NBR, and re-ABS/NBR/N15 were prepared using an internal mixer (Haake Polydrive, Germany) at 190°C and 45 rpm for Then, the molten samples were placed in a mold with dimensions of 12 cm x 12 cm x mm and compressed between two hot plates at 190°C under a pressure of 1,500 psi for The samples were then cooled to room temperature using cooling water Finally, the samples were taken out and cut into suitable shapes for the various ACCEPTED MANUSCRIPT tests The amounts of the different ingredients employed for the preparation of re-ABS, the re-ABS/NBR blend, and re-ABS/NBR/N15 nanocomposites are shown in Table 2.3 Measurements and characterizations Fourier transform infrared (FTIR) spectra were conducted using a NICOLET 6700 RI PT spectrometer (Thermo Scientific Co., USA) from 400 to 4,000 cm-1 with a resolution of cm-1 Scanning electron microscopy (SEM) images were used to observe the phase structure in the polymer blends and nanocomposites Cryo-fractured samples were obtained using liquid SC nitrogen and were analyzed by SEM (JSM 6600, JEOL Co., Japan) to examine the dispersion status of NBR and N15 in the re-ABS matrix Transmission electron (TEM) measurements M AN U were carried out on JEM-1400 Philips microscope (JEOL Co., Japan) to investigate the dispersion status of N15 in the resin matrix Specimens were microtomed using a Leica Ultracut UCT Wide angle X-ray diffraction (WAXD) patterns of samples were recorded in a 2θ angular range of 1.5-20° on a D8 Advance diffractometer (Bruker Co., Germany) employing Ni-filtered TE D CuKߙ radiation with a wavelength of 1.54 Å at 40 kV and 40 mA Differential scanning calorimetric (DSC) measurements were conducted in DSC equipment (Mettler Toledo Inc., USA) with a nitrogen flow rate of 30 cm3/min and heating rate of 10oC/min The thermal EP stability of the samples was carried out using TGA Q500 analyzer (TA Instruments Ltd., USA) All samples were heated under a nitrogen atmosphere in the temperature range of 25-700 oC at a AC C heating rate of 10 oC/min The tensile strength of all samples was evaluated by an AG-Xplus Series Precision Universal Tester (Shimadzu Inc., Japan) For the tensile test, the samples were prepared according to the ASTM D638 (type IV) standards All samples were kept in a desiccator under vacuum for 24 hour before the measurements At least specimens were tested for each composition to obtain mean values of mechanical parameters by employing statistical analysis ACCEPTED MANUSCRIPT The impact strength of all samples was measured according to ASTM D256 standards, using a Model IT504 Impact Tester (Tinius Olsen Inc., USA) At least notched test specimens for each composition were used for Izod measurement The impact strength value is calculated as the ratio of impact energy absorption to cross-section area of test specimen The impact strength RI PT (toughness) indicates the ability of a material to absorb shock and impact energy before breaking The rheological properties of polymers provide necessary information of flow behavior SC regarding their process-ability Thus, the torque-rheometer analysis is an effective method to qualitatively study melt viscosity, viscosity-temperature dependence, degradation, and M AN U crosslinking of polymer based materials such as polymer blends, composites, and nanocomposites In this work, the torque values are monitored as a function of time during the melt mixing of materials using the Hakee Polydrive under typical processing conditions The torque essential to rotate the blades is measured using a dynamometer in terms of the Results and Discussion TE D viscosity of materials 3.1 Morphology and mechanical performance of the re-ABS/NBR blend EP The mechanical properties of the re-ABS/NBR blends with the various NBR contents are shown in Fig The tensile modulus and strength were found to decrease remarkably with the AC C addition of NBR into the re-ABS matrix (Fig 2A) This behavior generally occurs in polymer blends based on the addition of an elastomer into a thermoplastic matrix because of the soft nature and diluting effect of the disperse phase [6-9] In contrast, the addition of NBR caused a significant improvement of the impact strength of the blend (Fig 2B) In particular, the impact strength of the blends increased and reached a maximum value of 52.7 KJ/m2 at a NBR of 10 wt% when compared to neat re-ABS (34 KJ/m2) In order to determine the possible reasons ACCEPTED MANUSCRIPT which lead to an improvement of the impact strength of the blend, fractured surfaces of re-ABS and the re-ABS/NBR (90/10) blend were evaluated by SEM It was observed that the partial degradation of rubber parts in the melt processing step resulted in the presence of a significant amount of voids in re-ABS (Fig 3A and 3C) [35, 36] Meanwhile, a relatively smooth fractured RI PT surface was observed in the case of the re-ABS/NBR (90/10) blend after NBR was added into the re-ABS matrix, suggesting the miscibility of re-ABS with NBR (Fig 3B and 3D) [37] NBR domains effectively filled the voids and was uniformly distributed in the re-ABS matrix (Fig SC 3D) We suggest that NBR effectively replaced the role of the degraded rubber parts of the ABS structure to result in better stress transferring across the interfaces in the blend [38], leading to M AN U the improvement of the impact strength of the materials To deeply understand the morphology, structure, and properties of the re-ABS/NBR blend in the presence of N15, the re-ABS/NBR (90/10) blend was used for further experiments 3.2 Morphology, structure, and properties of re-ABS/NBR/N15 nanocomposites TE D 3.2.1 Mechanical performance Fig shows the mechanical properties of the re-ABS/NBR blend and re-ABS/NBR/N15 nanocomposites with different N15 contents (1, 3, and phr) The addition of N15 into the EP re-ABS/NBR blend resulted in a significant change of the mechanical behavior of the nanocomposites The tensile modulus of the nanocomposites was improved compared to that of AC C the re-ABS/NBR (90/10) blend and it tended to increase when the N15 content was increased from to phr This result could be a consequence of the hindering effect on the mobility of matrix chains [39] and the high mechanical parameter of rigid nanofillers [40] In addition, the tensile strength and impact strength of the nanocomposites also increased and the best value was obtained with phr N15 The values of the tensile strength and impact strength were 6% and 8% higher, respectively, compared to the re-ABS/NBR (90/10) blend These results are in ACCEPTED MANUSCRIPT good agreement with the dispersion status of N15 throughout the matrix resin observed in the XRD, TEM, and SEM analyses However, when the N15 loading was increased to and phr, noticeable reductions of the tensile strength and impact strength of the nanocomposites were observed This result may be related to the presence of larger intercalated tactoids and RI PT aggregation formation of N15 (as shown by TEM) at a high content, which has a negative influence on the toughness of systems Slightly higher tensile strength and lower tensile modulus and impact strength values compared to re-ABS/NBR/N15 nanocomposites were also SC observed in studies conducted by Deeptimayee Mahanta et al and Mohammad Rahimi et al to recycle ABS [41, 42] M AN U 3.2.2 XRD analysis XRD was employed to evaluate the dispersibility of N15 in the nanocomposites (Fig 5) The observation of dispersion and distribution of N15 can help in understanding the mechanism for the morphological change with the addition of N15 The primary diffraction of neat N15 was TE D observed at 2.75o, corresponding to an interlayer spacing of 3.23 nm In the case of the re-ABS/N15 and NBR/N15 nanocomposites (Fig 5A), the diffraction positions respectively appeared at 2.50 o and 2.26 o which were lower than that of neat N15, indicating that NBR and EP ABS chains are intercalated into the interlayer spacing of the N15 tactoids [39] This also implies that N15 exhibited a slightly, although not significantly, better affinity with NBR than AC C the re-ABS chains In the case of re-ABS/NBR/N15 nanocomposites, the diffraction position shifted toward lower angles for all nanocomposites when compared to that of N15, exhibiting an increased d-spacing (Fig 5B) These results indicate that polymer chains were intercalated between the clay galleries to form an intercalated structure Furthermore, it was observed that the d-spacing in the intercalated tactoids depends on the N15 loading and the best value was obtained with phr N15 Poorer dispersion of N15 occurred when the clay loading was ACCEPTED MANUSCRIPT 3239-3246 [49] Chakraborty S, Bandyopadhyay S, Ameta R, Mukhopadhyay R, Deuri AS Application of FTIR in characterization of acrylonitrile-butadiene rubber (nitrile rubber) Polym Test 2007; 26: 38-41 Y, Alhassan SM, Yang VH, Schiraldi DA Polyether-block-amide RI PT [50] Wang copolymer/clay films prepared via a freeze-drying method Compos Part B-Eng 2013; 45: 625-630 SC [51] Zundel GG Hydration and Intermolecular Interactions, Infrared Investigations with Polyelectrolyte Membranes, Academic Press, New York, 1969 M AN U [52] An QF, Qian JW, Sun HB, Wang LN, Zhang L, Chen HL Compatibility of PVC/EVA blends and the pervaporation of their blend membranes for benzene/cyclohexane mixtures J Membr Sci 2003; 222: 113-22 [53] Bershtein VA, Egorova LM, Yakushev PN, Georgoussis G, Kyritsis A, Pissis P, Sysel P, TE D Brozova L Molecular dynamics in nanostructured polyimide-silica hybrid materials and their thermal stability Polym Sci 2002; 40: 1056-69 [54] Kourkoutsaki T, Logakis E, Kroutilova I, Matejka L, Nedbal J, Pissis P, Polymer in rubbery epoxy EP dynamics networks/polyhedral oligomeric silsesquioxanes nanocomposites Applied Polym Sci 2009; 113: 2569-82 AC C [55] Rotrekl J, Matjka L, Kaprálková L, Zhigunov A, Hromádková J, Kelnar I Epoxy/PCL nanocomposites: Effect of layered silicate on structure and behavior Express Polym Lett 2012; 6: 975-86 [56] Dikobe DG and Luyt AS Comparative study of the morphology and properties of PP/LLDPE/wood powder and MAPP/LLDPE/wood powder polymer blend composites Express Polym Lett 2010; 4: 729-41 21 ACCEPTED MANUSCRIPT [57] Chiu FC, Fu SW, Chuang WT, Sheu HS Fabrication and characterization of polyamide 6,6/organo-montmorillonite nanocomposites with and without a maleated polyolefin elastomer as a toughener Polym 2008; 49: 1015-26 [58] Chiu FC, Yea HZ, Chen CC Phase morphology and physical properties of AC C EP TE D M AN U SC compatibilizer Polym Test 2010; 29: 706-16 RI PT PP/HDPE/organoclay (nano) composites with and without a maleated EPDM as a 22 M AN U SC RI PT ACCEPTED MANUSCRIPT AC C EP TE D Fig Photograph of samples and chemical structures of the ABS, NBR and nanofil N15 23 M AN U SC RI PT ACCEPTED MANUSCRIPT TE D Fig (A) Tensile strength and (B) impact strength of the re-ABS/NBR blends with various AC C EP NBR contents 24 M AN U SC RI PT ACCEPTED MANUSCRIPT AC C EP TE D Fig Fractured surfaces of (A, C) re-ABS and (B, D) re-ABS/NBR (90/10) 25 TE D M AN U SC RI PT ACCEPTED MANUSCRIPT Fig (A) Tensile modulus and (B) impact strength of the re-ABS/NBR/N15 nanocomposites AC C EP with various N15.contents 26 RI PT ACCEPTED MANUSCRIPT AC C EP TE D M AN U N15 and re-ABS/NBR/N15 with 1, 3, and phr N15 SC Fig (A) XRD results of neat N15, re-ABS/N15 and NBR/N15, (B) XRD results of neat 27 M AN U SC RI PT ACCEPTED MANUSCRIPT Fig TEM and HR-TEM micrographs of (A, D, G) re-ABS/NBR/N15 (90/10/1), (B, E, H) AC C EP TE D re-ABS/NBR/N15 (90/10/3), and (C, F, K) re-ABS/NBR/N15 (90/10/5) nanocomposites 28 RI PT ACCEPTED MANUSCRIPT Fig SEM images of the fractured surfaces of (A) re-ABS/NBR/N15 (90/10/1), (B) AC C EP TE D M AN U SC re-ABS/NBR/N15 (90/10/3) and (C) re-ABS/NBR/N15 (90/10/5) nanocomposites 29 M AN U SC RI PT ACCEPTED MANUSCRIPT Fig Torque curves of re-ABS, re-ABS/NBR (90/10) and re-ABS/NBR/N15 AC C EP TE D nanocomposites 30 M AN U SC RI PT ACCEPTED MANUSCRIPT Fig FT-IR spectra of (a) re-ABS, (b) NBR, (c) re-ABS/NBR (90/10), (d) re-ABS/NBR/N15 AC C EP TE D (90/10/1), (e) re-ABS/NBR/N15 (90/10/3) nanocomposites and (f) N15 31 M AN U SC RI PT ACCEPTED MANUSCRIPT Fig 10 DSC results of re-ABS, the re-ABS/NBR (90/10) blend, and re-ABS/NBR/N15 AC C EP TE D nanocomposites 32 AC C EP TE D M AN U SC RI PT ACCEPTED MANUSCRIPT Fig 11 (A) TGA and (B) DTG results of re-ABS, the re-ABS/NBR (90/10) blend, and re-ABS/NBR/N15 nanocomposites 33 ACCEPTED MANUSCRIPT Table The amounts of the different components in re-ABS, the re-ABS/NBR blend, and re-ABS/NBR/N15 nanocomposites re-ABS (g) NBR (g) N15 (g) re-ABS 50 0 re-ABS/NBR (95/5) 47.5 2.5 re-ABS/NBR (90/10) 45 re-ABS/NBR (85/15) 42.5 7.5 re-ABS/NBR/N15 (90/10/1) 45 0.5 re-ABS/NBR/N15 (90/10/3) 45 1.5 re-ABS/NBR/N15 (90/10/5) 45 SC RI PT Sample AC C EP TE D M AN U 34 2.5 ACCEPTED MANUSCRIPT Table Glass transition temperatures of re-ABS, re-ABS/NBR (90/10), and re-ABS/NBR/N15 nanocomposites Tg of re-ABS (0C) re-ABS 101.78 re-ABS/NBR (90/10) 100.40 re-ABS/NBR/N15 (90/10/1) 96.08 94.22 99.49 AC C EP TE D M AN U re-ABS/NBR/N15 (90/10/5) SC re-ABS/NBR/N15 (90/10/3) RI PT Sample 35 ... various N15. contents 26 RI PT ACCEPTED MANUSCRIPT AC C EP TE D M AN U N15 and re -ABS/ NBR /N15 with 1, 3, and phr N15 SC Fig (A) XRD results of neat N15, re -ABS/ N15 and NBR /N15, (B) XRD results of neat... Morphology, structure, and properties of re -ABS/ NBR /N15 nanocomposites TE D 3.2.1 Mechanical performance Fig shows the mechanical properties of the re -ABS/ NBR blend and re -ABS/ NBR /N15 nanocomposites. ..ACCEPTED MANUSCRIPT Enhanced Mechanical and Thermal Properties of Recycled ABS/ Nitrile Rubber/ Nanofil N15 Nanocomposites Nguyen Dang Mao, a Tran Duy Thanh, a,b