Polym. Bull. (2013) 70:2829–2841 DOI 10.1007/s00289-013-0991-3 ORIGINAL PAPER
Compatibility of waste rubber powder/polystyrene blends by the addition of styrene grafted styrene butadiene rubber copolymer: effect on morphology and properties Jinlong Zhang • Hongxiang Chen • Yu Zhou Changmei Ke • Huizhen Lu
•
Received: 4 October 2011 / Accepted: 30 May 2013 / Published online: 12 June 2013 Ó Springer-Verlag Berlin Heidelberg 2013
Abstract Waste rubber powder/polystyrene (WRP/PS) blends with different weight ratio were prepared with styrene grafted styrene butadiene rubber copolymer (PS-g-SBR) as a compatibilizer. The graft copolymer of PS-g-SBR was synthesized by emulsion polymerization method and confirmed through Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC). The copolymer at different weight ratio was subsequently added into the blends. The effects of weight ratio of WRP/PS and compatibilizer loading on mechanical properties were investigated. PS/WRP blends in a weight ratio of 80/20 showed higher impact strength. Moreover, the impact strength of the blend materials increased with the addition of SBR-g-PS, however, decreased at a high loading of the copolymer. The morphology and thermal properties of WRP/PS blends were examined by DSC, scanning electron microscopy (SEM), thermogravimetry (TG). DSC indicated that compared with PS/WRP blend, the glass transition temperature (Tg) of PS matrix phase in PS/WRP/SBR-g-PS blend shifted to low temperature because of the formation of chemical crosslinks or boundary layer between PS and WRP, and the Tg of WRP phase of both the PS/WRP and PS/WRP/SBR-g-PS blends did not appear. SEM results showed that interfacial adhesion in the blends with the PS-g-SBR copolymer was improved. The morphology was a typical continuous– discontinuous structure. PS and WRP presented continuous phase and discontinuous phase, respectively, indicating the moderate interface adhesion between WRP and J. Zhang H. Chen (&) Y. Zhou C. Ke H. Lu Hubei Key Laboratory of Coal Conversion and New Carbon Material, College of Chemical Engineering and Technology, Wuhan University of Science and Technology, Wuhan 430081, China e-mail:
[email protected] H. Chen Hubei Key Laboratory of Pollutant Analysis and Reuse Technology, Huangshi 435002, China H. Chen Fujian Key Laboratory of Polymer Materials, Fuzhou 350007, China
123
2830
Polym. Bull. (2013) 70:2829–2841
PS matrix. TG illustrated that the onset of degradation temperature in the PS/WRP/ PS-g-SBR blend decreased slightly by contrast with PS/WRP blend and the degradation of PS/WRP blends with and without SBR-g-PS was completed about at the same values. Keywords Compatibility Waste rubber powder Polystyrene Blend PS-g-SBR Morphology
Introduction Polystyrene (PS) is a widely used plastic for general purpose. The main advantages of polystyrene are good transparency, high stiffness, excellent processibility, and good dielectric properties, etc. The disadvantage is its low impact strength at low temperature. The incorporation of dispersed elastomeric particles in a rigid matrix can improve the impact resistance of PS [1], the toughening study of which has always been very important in polymer blending area [2]. Many rubbers, including ethylene-propylene-diene (EPDM) [3, 4], ethylenepropylene rubber (EPR) [5], natural rubber (NR) [6], polybutadiene rubber (PB) [7], acrylonitrile-butadiene rubber (ABR) [8], styrene-butadiene rubber (SBR) [9], etc., had been used to toughen PS. The two typical methods were used by the researchers. Due to the incompatibility of two phases, the overall performance of the blends can be improved by the addition of a suitable compatibilizer, namely the compatibilization of graft or block copolymers consisting of identical repeat units to homopolymer (A-g-B or A-b-B copolymer). For example, PS/EPR blends by addition of poly(styrene/ethylene-butylene) (SEB) and poly(styrene/ethylenepropylene) (SEP) diblock copolymer [10], PS/PB blends using PS-PB diblock and PS-PB-PS triblock copolymers ascompatibilizers [11], PS/NBR blends via adding to styrene-acrylonitrile copolymer as a compatibilizer [8]; in addition, the block copolymer with one end identical to homopolymer, another terminal segment miscibility with the homopolymer named as A/B/A-C system, for example, PS/ EPDM blends using SEP [12] and poly(styrene–butadiene–styrene) [13] as compatibilizers. In order to improve the compatibility of blends, in situ polymerization technique was also used. Lourenco et al. [14, 15] reported EPDM-toughened polystyrene by in situ polymerization, it was observed that as the EPDM concentration increased, the dispersed domain size decreased in the case of EPDM/PS blends. Toughening of PS by one sort of rubber is mostly used, but the investigation on toughening of PS with mixing rubbers is seldom reported. The generation of waste tire rubber has increased dramatically with the rapid development of vehicles in the past two decades [16, 17]. The accumulation of large quantities of waste tire has brought about serious environment problems. The waste tire rubber can be ground into a powder, which is a main method to utilization and recycling of waste tire rubber in large scale. With a view of expanding the applications of waste rubber powder (WRP), the utilization of WRP by means of blending with polymeric materials has become an important topic [18–20]. WRPfilled polymer partially retains the cost reduction and processability of polymers,
123
Polym. Bull. (2013) 70:2829–2841
2831
with improvement in the impact resistance. It is generally believed that the interfacial adhesion between the dispersed rubber particles and the polymer matrix plays an important role in the toughening of polymer. In general, the addition of WRP to polymer causes considerable deterioration of the mechanical properties because of low compatibility and poor interfacial adhesion between the WRP and polymer [21]. Several attempts were made to improve the interfacial compatibility of plastic matrix and waste rubber powder disperse phase with compatibilizers, such as ethylene vinyl acetate copolymer [22], styrene/ethylene-butylene/styrene [23], styrene/ethylene-butylene/styrene-g-maleic anhydride [24], dioctyl phthalate [25], liquid carboxyl-terminated butadiene acrylonitrile [26], etc. The two-component compatibilizers in the plastic and waste rubber powder blends, such as peroxide/ copolymer or curing agent/copolymer could improve the mechanical properties moderately, because of similar polar between block copolymer and matrix/disperse, and small molecules acted as crosslink agent [27–30]. Among the WRP/plastic blends using virgin rubber or EPDM as a compatibilizer with dynamic vulcanization had better mechanical properties, due to better interfacial adhesion between the blends [31, 32]. A number of works have also been reported by several researchers on PS/WRP blends with sorts of compatibilizers. Mou et al. [33] reported that impact strength of WRP toughened PS by reinforcing reaction technique was tenfold more than neat PS; however, only a few details about effects of WRP size and WRP content on the mechanical properties were discussed. Zhang and Sun [34] observed that PS and WRP blends hardly exceeded PS at the mechanical properties with simple mixing method or addition of silane coupling agent. According to the molecular construction, designing a compatibilizer of the blends was a proper method. Early report by Lu et al. [35] in the patent that using SBS, styrene/ethylene-butylene/styrene block copolymer, or polystyrene-maleic anhydride copolymer as compatibilizers, the impact strength of PS/WRP blends reached maximum at 51.2 J m-1, fivefold comparing to 9.6 J m-1 of neat PS. However, SBR-g-PS as a compatibilizer of the PS/WRP blends has not yet been reported. In this study, PS-g-SBR is prepared by emulsion polymerization method and characterized by Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC). The effects of mass ratio of PS/WRP, compatibilizer loading on the mechanical properties of WRP/PS blends are investigated. The glass transition temperature, surface fractured morphology and thermal properties of WRP/PS-g-SBR/PS and WRP/PS blends are characterized by DSC, SEM, and TG.
Experimental Materials Styrene (Tianjin Damao Chemical Co., Ltd, China) was washed with 5 wt% NaOH solution and dried with Na2SO4 before use. WRP (Jilin Huadian, China) was determined to be 80 mesh by the particle size analyzer. The recipes of WRP were listed in Table 1. WRP was extracted with acetone, washed with 5 wt% sodium
123
2832 Table 1 The recipes for surface grafting of WRP
Polym. Bull. (2013) 70:2829–2841
Ingredients
Content/wt%
Natural rubber
36.4
Styrene-butadiene rubber
15.1
Polybutadiene Oil Carbon black Ash
3.1 6.6 32.8 6.0
hydroxide solution, and 10 wt% hydrochloric acid in turn, and finally dried under vacuum to constant weight. Polystyrene was obtained from Zhanjiang Xinzhongmei chemical Co., Ltd. Styrene butadiene rubber latex with a solid content of about 40 wt% was supplied by Zibo Heli chemical Co. KD-1 (98 wt%) was prepared by our lab. K2S2O4 was supplied by Wuxi Minfeng agent Co., Ltd. and ammonia was supplied by Wuhan Zhongtian chemical Co., Ltd. Preparation of PS-g-SBR copolymer PS-g-SBR copolymer was synthesized by emulsion polymerization method under nitrogen atmosphere. SBR latex was added to the flask and charged with N2 for 1.5 h. The required amount of styrene monomer was added into an aqueous mixture of styrene butadiene rubber latex, and then the mixture was stirred for about 1 h to disperse well. The reaction was carried out at 80 °C for 4 h using K2S2O4 as an initiator and water as a medium. The synthesized graft copolymer was obtained by casting mixture on a glass plate and dried at ambient temperature. Dry films were cut into small pieces, and wrapped with filter paper. The gross graft copolymer was separated using a Soxhlet apparatus with a 1:1 mixture of butanone and hexamethylene for 48 h. The remaining polymer was considered as gel. The insoluble residue was dried under vacuum to a constant weight at 50–60 °C. Preparation of PS/WRP blends Polystyrene and waste rubber powder were mixed in a single screw extruder. The temperature of the screws and the die was maintained between 160 and 190 °C. The extrudate was then quenched in cold water, and granulated. The impact and tensile samples were prepared by injection molding between 180 and 200 °C. Characterization FTIR Fourier transform infrared spectroscopy spectra of PS, SBR and PS-g-SBR copolymer were collected using a Nicolet-5700 FTIR spectrometer (Thermo Fisher Scientific) in the range of 4,000–400 cm-1.
123
Polym. Bull. (2013) 70:2829–2841
2833
DSC The glass transition temperatures of PS, SBR, PS-g-SBR copolymer, PS/PS-g-SBR/ WRP and PS/WRP blends were measured by a DSC-60 differential scanning calorimeter (Shimadzu) within the range of -100 to 150 °C at a heating rate of 10 °C min-1 under a continuous nitrogen flow. SEM The fracture surfaces from the impact testing of the PS/WRP/PS-g-SBR blend samples were characterized with a Nova400Nano SEM (Philips Electron Optics). The samples were sputtered with gold before observing. TG Thermogravimetry curves of the samples were recorded by a STA449/6/G thermogravimetric analyzer (NaiChi). The PS/PS-g-SBR/WRP and PS/WRP blends were heated up to 750 °C at the heating rate of 15 °C min-1 using a nitrogen atmosphere. Tensile and impact resistance tests The impact strength was measured according to Chinese National Standard GB 1843 with a ZWJ-0350 impact machine. Each impact specimen had dimensions of 80 9 10 9 4 mm. Tensile strength measurement was performed on dumbbell specimens at ambient temperature according to Chinese National Standard GB 1040 using an UTM 6503 Universal Materials Testing Machine. The measurements error was less than ±5 % for tensile strength and ±10 % for impact strength.
Results and discussion Characterization of PS-g-SBR FTIR The attenuated total reflectance FTIR spectra of PS, SBR, PS-g-SBR are shown in Fig. 1. The FTIR spectrum of PS shows the peak at 3,026 cm-1 corresponds to aromatic C–H stretching, the bands at 2,924 and 2,855 cm-1 are assigned to C–H of CH2, the peaks at 1,601, 1,492 and 1,452 cm-1 are attributed to aromatic skeleton stretching, the bands at 1,600–1,950 cm-1 are the characteristic frequency multiplication and combination phenomena of PS. It is seen from the FTIR spectrum of SBR that the peaks at 696, 758 cm-1 correspond to monosubstituted benzene, the peak at 3,021 cm-1 corresponds to aromatic C–H stretching, the aromatic structure of styrene unit is provided. The peak at 1,653 cm-1 is assigned to stretching vibration of C=C, the peaks at 966 and 910 cm-1 are corresponding to
123
2834
Polym. Bull. (2013) 70:2829–2841
Fig. 1 Attenuated total reflectance FTIR spectra of PS, SBR, and PS-g-SBR
trans CH wagging and vinyl CH2 wagging, respectively. The FTIR spectrum of PSg-SBR shows the peaks at 698, 758, 804 cm-1 corresponding to monosubstituted or 1,4-disubstituted benzene, and also presents the characteristic bands at 1,600–1,950 cm-1 of PS. The above analysis demonstrates that the styrene has been grafted onto the SBR. DSC Differential scanning calorimetry curves of PS, SBR, and PS-g-SBR copolymer are shown in Fig. 2, the glass transition temperatures of PS, SBR, and PS-g-SBR are listed in Table 2. From Fig. 2, it is noted that PS and SBR have only one glass transition temperature, with respect to 98.1 and -41.9 °C, respectively. However, PS-g-SBR copolymer has two glass transition temperatures, the lower one belongs to SBR phase and the high one relates to PS phase. This result further proves the existence of the grafted layer of PS-g-SBR copolymer. Effect of PS-g-SBR on compatibility and morphology of WRP/PS blends DSC The DSC curves of WRP, PS/WRP and PS/WRP/PS-g-SBR blends are shown in Fig. 3. The glass transition temperature of the each individual polymer has been found for PS 98.1 °C (see Fig. 2), for WRP -58.5 °C. Analysis of DSC curve of PS based blends shows that mixing of WRP and PS leads to shift of Tg of PS component to higher temperature from 98.1 to 103.2 °C, but the Tg of WRP component does not clearly occur in the DSC curve. The change in relaxation
123
Polym. Bull. (2013) 70:2829–2841
2835
Fig. 2 DSC curves of PS, SBR, and PS-g-SBR copolymer Table 2 Tgs of PS, SBR and PS-g-SBR copolymer
Samples
Tg1 of rubber phase/ °C
Tg2 of plastic phase/ °C
SBR
-41.9
–
PS-g-SBR
-45.3
81.7
PS
–
98.1
behavior of PS component can be explained by interpenetrating of polymer chains of the components, hampering segmental mobility of PS chains. For compatibilized PS/WRP/SBR-g-PS blend, shift of Tg values by 0.7 °C of PS matrix phase to lower temperature is observed compared to uncompatibilized PS/WRP blend, the Tg of WRP phase of the compatibilized blend does also not appear in the DSC curve. The results indicate a reducing of molecular (segmental) mobility of the component polymer chains due to the formation of a number of chemical crosslinks or boundary layer between PS and WRP during the reactive compatibilization. SEM The SEM photographs of fracture surface of the PS/WRP blends with and without the compatibilizer of PS-g-SBR are shown in Fig. 4. From Fig. 4a, b, the domain size of dispersed phase is large, the particles are easily pulled out from the matrix phase, and concave holes exist on the fracture surfaces, indicating a lack of interaction between PS matrix and WRP dispersed phase. In Fig. 4c, d, it is clear that the fractured surface of PS/WRP blends with some amount of PS-g-SBR as a compatibilizer becomes smooth, meanwhile the apparent size of the WRP particles is reduced and well incorporated into the matrix. Moreover, the WRP phases seem to adhere strongly to the PS matrix, illustrating that the PS-g-SBR copolymer acts as
123
2836
Polym. Bull. (2013) 70:2829–2841
Fig. 3 DSC curves of PS/WRP and PS/PS-g-SBR/WRP blends
an efficient compatibilizer, also suggesting better dispersion of the WRP in the PS and higher interfacial adhesion between two phases. Consequently, the incorporation of PS-g-SBR copolymer can improve the compatibility of the PS/WRP blend. Mechanical properties of PS/WRP blends with and without compatibilizers WRP/PS weight ratio The mechanical properties of the PS/WRP blends are shown in Table 3. In PS/WRP binary blends, the tensile strength decreases due to the low tensile strength of elastomer, but the impact strength increases, and then decreases. This may be attributed to the poor adhesion between WRP and PS, and thereby the large particles make an easy way for the rapid propagation of cracks and lead to a large fall in the tensile strength. The impact strength increases with increasing in the WRP loading, which can be attributed to the increase in the amount of elastic (or bending) deformation before the onset of ductile deformation. When the waste rubber powder increases in the blends system, matrix alters from PS to PS/WRP blend, WRP acts as filler and matrix, the impact strength of blends increases with the increase of elastomers. Compatibilizer content The effect of the compatibilizer content on the mechanical properties is shown in Table 4. An increase in the impact strength is observed when PS-g-SBR is introduced into the PS/WRP blends, and the tensile strength of the PS/PS-g-SBR/ WRP blends is improved with adding PS-g-SBR, with high loading of PS-g-SBR,
123
Polym. Bull. (2013) 70:2829–2841
2837
Fig. 4 SEM pictures of PS/WRP blends with and without PS-g-SBR: a PS/WRP 9500, b PS/WRP 92,000, c PS/WRP/PS-g-SBR 9500 and d PS/WRP/PS-g-SBR 92,000 Table 3 Effect of WRP content on the mechanical properties
WRP content/wt%
Impact strength/kJ m-2
Tensile strength/MPa
5
7.2
23.2
10
7.5
25.1
15
6.5
19.1
20
10.1
18.9
25
10.0
17.5
30
6.3
16.4
35
7.0
15.0
the tensile strength decreases. In PS/WRP/PS-g-SBR blends, all particles size reduction and an improvement of interfacial adhesion, caused by the formation of PS-g-SBR copolymer at the interface between PS and WRP, seem to lead to the improvement of the mechanical properties. It is widely accepted that a compatibilizer has two main roles, which are prevention of coalescence and reduction of
123
2838 Table 4 Effect of compatibilizer on the mechanical properties of blends
Polym. Bull. (2013) 70:2829–2841
PS-g-SBR content/wt%
Impact strength/kJ m-2
Tensile strength/MPa
3
3.5
19.0
5
3.5
18.2
10
4.4
15.2
15
3.8
14.0
20
5.6
13.1
25
3.8
13.4
Fig. 5 Schematic model illustrating the location of the PS-g-SBR at the blend interface
the interfacial tension. It is presumed that interfacial strength in the blends is determined primarily by interaction of the compatibilizer with WRP, since adhesion to PS is provided by bonding linkages. The interaction of PS-g-SBR with WRP is strength enough to sustain particle–matrix adhesion, as the compatibilizer is drawn along with the WRP. In addition, the presence of compatibilizer at the interface broadens the interfacial region through penetration of the copolymer chains into the adjacent phase. The most ideal reaction of the graft copolymer is given in Fig. 5. Thermal properties of PS/WRP blends with and without compatibilizers From TG thermograms, the initial and final thermal decomposition temperature of WRP/PS blends with and without PS-g-SBR as a compatibilizer are determined as shown in Fig. 6. It can be seen that there is a slight difference between both blends. It shows that from TG curves, the onset of degradation of PS/WRP blend, starts at 423 °C, while the onset of degradation temperature reduces about 1 °C in the case of PS/WRP/PS-g-SBR blend with the starting degradation temperature at 422 °C. The degradation of PS/WRP blends with and without SBR-g-PS is completed at about 500 °C, respectively. The weight loss between 422 and 500 °C represents the occurrence of random chain scission and intermolecular transfer, which leads to the formation of volatile products [36]. It can be explained that added PS-g-SBR copolymer in the blends, the PS-block of the copolymer is miscible with the PS phase and the SBR-block has relatively
123
Polym. Bull. (2013) 70:2829–2841
2839
Fig. 6 TG curves of PS/WRP and PS/WRP/PS-g-SBR blends
high affinity with the WRP phase [13]. As the formation of boundary layer between PS and WRP, the onset decomposition starts with the bond layer between SBR-g-PS and PS or SBR-g-PS with WRP, hence, the decomposition temperature decreases slightly compared with the blend based on PS and WRP. Consequently, the incorporation of PS-g-SBR can improve the compatibility of the PS/WRP blend. This improvement in compatibility between PS and WRP after addition of SBR-gPS copolymer is in agreement with the morphology observation and schematic model about the interface layer in Fig. 5.
Conclusions In this research, polystyrene-grafted SBR copolymer was synthesized via emulsion polymerization using K2S2O4 as an initiator. PS-g-SBR copolymer was characterized by FTIR and DSC, and the results showed that PS was grafted onto the SBR. Thermoplastic elastomer blends from WRP and PS at various blending ratios were prepared. The blends were compatibilized with various amounts of PS-g-SBR copolymers. The prepared blends were investigated for their mechanical, thermal properties, and morphology. The impact strength of PS/WRP blends were improved with the addition of PS-g-SBR as the compatibilizer. SEM results showed that the interfacial adhesion of blends compatibilized with the PS-g-SBR copolymer improved. The morphology was a typical continuous–discontinuous structure. PS and WRP presented continuous phase and discontinuous phase, respectively. DSC indicated that for compatibilized PS/WRP/SBR-g-PS blend, Tg of PS matrix phase in PS/WRP/SBR-g-PS blend shifted to low temperature about 0.7 °C compared to PS/WRP blend because of the formation of chemical crosslinks or boundary layer between PS and WRP, and the Tg of WRP phase in both the PS/WRP/SBR-g-PS and PS/WRP blends did not appear. TG illustrated that the onset of degradation temperature in the PS/WRP/PS-g-SBR blend decreased about 1 °C by contrast with
123
2840
Polym. Bull. (2013) 70:2829–2841
PS/WRP blend, and the degradation of PS/WRP blends with and without SBR-g-PS was completed at about 500 °C, respectively. Acknowledgments The authors are thankful to Hubei Key Laboratory of Pollutant Analysis and Reuse Technology (KY2010G18) and Fujian Key Laboratory of Polymer Materials (FJKL-POLY201201) for the financial support.
References 1. Lourenco E, Felisberti MI (2006) Thermal and mechanical properties of in situ polymerized PS/ EPDM blends. Eur Polym J 42(10):2632–2645 2. Liu YQ, Zhang XH, Gao JM, Huang F, Tan BH, Wei GS, Qiao JL (2004) Toughening of polypropylene by combined rubber system of ultrafine full-vulcanized powdered rubber and SBS. Polymer 45(1):275–286 3. Shaw S, Singh RP (1990) Studies on impact modification of polystyrene (PS) by ethylene-propylenediene (EPDM) rubber and its graft copolymers. I. PS/EPDM and PS/EPDM-g-styrene blends. J Appl Polym Sci 40(5–6):685–692 4. Shaw S, Singh RP (1990) Studies on impact modification of polystyrene (PS) by ethylene-propylenediene (EPDM) rubber and its graft copolymers. II. PS/EPDM-g-(styrene-co-methylmethacrylate) blends. J Appl Polym Sci 40(5–6):693–699 5. Polizu S, Favis BD, Vu-Khanh T (1999) Morphology-interface-property relationships in polystyrene/ ethylene-propylene rubber blends. 2. Influence of areal density and interfacial saturation of diblock and triblock copolymer interfacial modifiers. Macromolecules 32(10):3448–3456 6. Neoh SB, Hashim AS (2004) Highly grafted polystyrene modified natural rubber as toughener for polystyrene. J Appl Polym Sci 93(4):1660–1665 7. Gao GH, Zhao WZ, Zhao YN, Zhang HX (2007) Sub-micron core-shell rubber particles modified polystyrene-effects of grafting degree on morphology and mechanical property. Acta Materiae Compositae Sinica 24(2):33–37 8. Mathew M, Thomas S (2003) Compatibilisation of heterogeneous acrylonitrile–butadiene rubber/ polystyrene blends by the addition of styrene- acrylonitrile copolymer: effect on morphology and mechanical properties. Polymer 44(4):1295–1307 9. Scuracchio CH, Bretas RES, Isayev AI (2004) Blends of PS with SBR devulcanized by ultrasound: rheology and morphology. J Elastom Plast 36(1):45–75 10. Cigana P, Favis BD, Albert C, Vu-Khanh T (1997) Morphology-interface-property relationships in polystyrene/ethylene-propylene rubber blends. 1. Influence of triblock copolymer interfacial modifiers. Macromolecules 30(14):4163–4169 11. Mathur D, Nauman EB (1999) Impact strength of bulk PS/PB blends: compatibilization and fracture studies. J Appl Polym Sci 72(9):1151–1164 12. Crevecoeur JJ, Nelissen L, van der Sanden MCM, Lemstra PJ, Mencer HJ, Hogt AH (1995) Impact strength of reactively extruded polystyrene/ethylene-propylene-diene rubber blends. Polymer 36(4):753–757 13. Fang ZP, Guo ZH, Zha LL (2004) Toughening of polystyrene with ethylene-propylene-diene terpolymer (EPDM) compatibilized by styrene-butadiene-styrene block copolymer (SBS). Macromol Mater Eng 289(8):743–748 14. Lourenc¸o E, Felisberti MI (2006) Thermal and mechanical properties of in situ polymerized PS/ EPDM blends. Eur Polym J 42(10):2632–2645 15. Lourenc¸o E, Gonc¸alves MC, Felisberti MI (2009) Dynamic mechanical properties and morphological structure of PS/EPDM blends prepared by in situ polymerization of styrene. J Appl Polym Sci 112(4):2280–2289 16. Shanmugharaj AM, Kim JK, Ryu SH (2007) Modification of rubber powder with peroxide and properties of polypropylene/rubber composites. J Appl Polym Sci 104(4):2237–2243 17. Lee SH, Hwang SH, Kontopoulou M, Sridhar V, Zhang ZX, Xu D, Kim JK (2009) The effect of physical treatments of waste rubber powder on the mechanical properties of the revulcanizate. J Appl Polym Sci 112(5):3048–3056 18. Naskar AK, Bhowmic AK, De SK (2002) Melt-processable rubber: chlorinated waste tire rubber filled polyvinyl chloride. J Appl Polym Sci 84(3):622–631
123
Polym. Bull. (2013) 70:2829–2841
2841
19. Naskar AK, Bhowmick AK, De SK (2001) Thermoplastic elastomeric composition based on ground rubber tire. Polym Eng Sci 41(6):1087–1098 20. Hassan MM, Aly RO, Hasanen JA, El Sayed ESF (2010) Influence of talc content on some properties of gamma irradiated composites of polyethylene and recycled rubber wastes. J Appl Polym Sci 117(4):2428–2435 21. Sonnier R, Leroy E, Clerc L, Bergereta A, Lopez-Cuesta JM (2007) Polyethylene/ground tyre rubber blends: influence of particle morphology and oxidation on mechanical properties. Polym Test 26(2):274–281 22. Me´sza´ros L, Ta´bi T, Kova´cs JG, Ba´ra´ny T (2008) The effect of EVA content on the processing parameters and the mechanical properties of LDPE/ground rubber blends. Polym Eng Sci 48(5):868–874 23. Phinyocheep P, Axtell FH, Laosee T (2002) Influence of compatibilizers on the mechanical crystallization, and morphology of polypropylene/scrap rubber dust blends. J Appl Polym Sci 86(1):148–159 24. Lee SH, Balasubramanian M, Kim JK (2007) Dynamic reaction inside co-rotating twin screw extruder. II. Waste ground rubber tire powder/polypropylene blends. J Appl Polym Sci 106(5):3209–3219 25. Ghaisas SS, Kale DD, Kim JG, Jo BW (2004) Blends of plasticized poly(vinyl chloride) and waste flexible poly(vinyl chloride) with waste nitrile rubber powder. J Appl Polym Sci 91(3):1552–1558 26. Boynton MJ, Lee A (1997) Fracture of an epoxy polymer containing recycled elastomeric particles. J Appl Polym Sci 66(2):271–277 27. Abadchi MR, Aranj AJ, Nazockdast H (2010) Partial replacement of NR by GTR in the thermoplastic elastomer based on LLDPE/NR through using reactive blending: its effects on morphology, rheological, and mechanical properties. J Appl Polym Sci 115(4):2416–2422 28. Cao Y, Qiu QH, Guo BC, Jia DM (2003) The preparation of ground rubber/LLDPE elastomer alloy. China Synth Resin Plast 20(1):1–5 29. Zhang ZX, Sridhar V, Kim JK (2008) Polypropylene-waste ground tire powder microcellular composites: effect of processing variables on morphology and physico-mechanical properties. Polym Compos 29(11):1276–1284 30. Li Y, Zhang Y, Zhang YX (2003) Mechanical properties of high-density polyethylene/scrap rubber powder composites modified with ethylene-propylene-diene terpolymer, dicumyl peroxide, and silicone oil. J Appl Polym Sci 88(8):2020–2027 31. Kumar CR, Fuhmann I, Kocsis JK (2002) LDPE-based thermoplastic elastomers containing ground tire rubber with and without dynamic curing. Polym Degrad Stab 76(1):137–144 32. Grigorveva OP, Fainleib AM, Tolstov AL, Starostenko OM, Lievana E, Karger-Kocsis J (2005) Thermoplastic elastomers based on recycled high-density polyethylene, ethylene-propylene-diene monomer rubber, and ground tire rubber. J Appl Polym Sci 95(3):659–671 33. Mou SS, Tu M, Qin BH, Huang H (2002) Rubber crumb toughened polystyrene prepared by reinforcing reaction molding. China Synth Rubber Ind 25(6):382 34. Zhang BW, Sun XL (2003) Study on the properties of waste rubber powder and polystyrene blends. China Rubber Ind 50(9):529–531 35. Lu X, Wang XL, Jiang HW (2009) The method of preparing blend material based on waste rubber powder and polystyrene. Chinese Patent CN 101602874A 36. Awang M, Ismail H, Hazizan MA (2007) Polypropylene-based blends containing waste tire dust: effects of trans-polyoctylene rubber (TOR) and dynamic vulcanization. Polym Test 26(6):779–787
123
