On the compatibility of polystyrene/acrylonitrile-butadiene-g-styrene copolymer/solvent system

Summary Influence of the temperature on the compatibility of the polystyrene / AB-g-S graft copolymer / cyclohexanone have been studied by light scattering and viscosity measurement. It was established that the compatibility of components is changed in the temperature range where the conformational transitions take place.     

Epoxy/acrylonitrile-butadiene-styrene copolymer/clay ternary nanocomposite as impact toughened epoxy

Epoxy resins have low impact strength and poor resistance to crack propagation, which limit their many end use applications. The main objective of this work is to incorporate both acrylonitrile-butadiene-styrene copolymer (ABS) and organically modified clay (Cloisite 30B) into epoxy matrix with the aim of obtaining improved material with the impact strength higher than neat epoxy, epoxy/clay and epoxy/ABS hybrids without compromising the other desired mechanical properties such as tensile strength and modulus. Impact and tensile properties of binary and ternary systems were investigated. Tensile strength, elongation at break and impact strength were increased significantly with incorporation of only 4 phr ABS to epoxy matrix. For epoxy/clay nanocomposite with 2.5% clay content, tensile modulus and strength, and impact strength were improved compared to neat epoxy. With incorporation of 2.5% clay and 4 phr ABS into epoxy matrix, 133% increase was observed for impact strength. Ternary nanocomposite had impact and tensile strengths greater than values of the binary systems. Morphological properties of epoxy/ABS, epoxy/clay and epoxy/ABS/clay ternary nanocomposite were studied using atomic force microscopy (AFM) phase imaging, scanning electron microscopy (SEM) and wide angle X-ray diffraction (WAXD). New morphologies were achieved for epoxy/ABS and epoxy/ABS/clay hybrid materials. Exfoliated clay structure was obtained for epoxy/clay and epoxy/ABS/clay nanocomposite.     

尼龙66/乙烯-醋酸乙烯酯共聚物接枝马来酸酐共混体系的研究(Ⅰ)乙烯-醋酸乙烯酯共聚物熔融接枝马来酸酐的制备与表征

以马来酸酐为单体、过氧化物为引发剂，采用熔融挤出法制备了乙烯-醋酸乙烯酯共聚物接枝马来酸酐(EVA-g-MAH)。重点讨论了不同型号的EVA、过氧化物引发剂品种及用量、单体MAH用量和加工工艺条件等因素时接枝反应的影响。通过化学滴定法和傅立叶红外光谱法(FTlR)证实部分马来酸酐确实以化学键连接到EVA分子链上。与聚乙烯(PE)、聚丙烯(PP)相比，EVA中由于含有醋酸乙烯(VA)基团，极性较大，与MAH的相客性较好，因而在相同的条件下接枝效率也更大；而且VA含量越大，越有利于接枝反应。比较不同的过氧化物引发剂BPO和DCP。发现DCP的引发效果更好。实验结果还表明，在EVA进行接枝反应的同时存在着交联反应，引发剂DCP的用量不宜过高，为得到接枝率适中，交联度很小的接枝产物，还要选择合适的MAH与DCP的用量。     

吸水膨胀型丙烯腈-丁二烯-苯乙烯共聚物/丁腈橡胶热塑性硫化胶的性能及微观形貌

以交联聚丙烯酸钠（CPNa AA）为吸水材料,通过动态硫化法制备了基于丙烯腈-丁二烯-苯乙烯共聚物（ABS）/丁腈橡胶（NBR）/氯化聚乙烯（CM）热塑性硫化胶（TPV）的吸水膨胀橡胶（WSR）,考察了CPNa AA用量对WSR物理机械性能和吸水性能的影响,研究了WSR的微观形貌。结果表明,在实验范围内,ABS/NBR/CM/CPNa AA WSR的应力-应变行为均表现出＂软而韧＂的弹性体特征,随着CPNa AA用量的增加,WSR的拉伸强度、扯断伸长率、永久变形和撕裂强度均呈下降趋势,邵尔A硬度略有提高,WSR的吸水率、吸水速率及脱水失重率提高,当CPNa AA用量为70份时,室温下95 h WSR即达到吸水平衡状态,此时吸水率为369.8%;与第1次的最大吸水率相比,第2次及第3次的最大吸水率仅有小幅降低,但第2次及第3次的初始吸水速率远大于第1次的初始吸水速率,脱水失重率明显降低;CPNa AA在TPV中分散均匀,未出现团聚现象,但表面结构松散,与TPV之间的界面作用较弱;WSR吸水干燥后表面出现明显的缝隙和孔洞。     

苯乙烯-异戊二烯-苯乙烯嵌段共聚物及其接枝马来酸酐增韧聚苯乙烯/纳米碳酸钙复合材料

以过氧化二异丙苯（DCP）为引发剂,通过单螺杆挤出机熔融挤出,制备了苯乙烯-异戊二烯-苯乙烯接枝马来酸酐（SIS—MAH）,研究了SIS及SIS—MAH对聚苯乙烯（Ps）／纳米碳酸钙（nano—CaCO3）复合材料物理、力学性能的影响,对其结构进行了表征。结果表明,MAH的用量宜为SIS质量分数的3％,DCP的用量应小于MAH质量分数的0．3％;当1份nano—CaCO3加入到PS／SIS（质量比100／2）复合材料3中,SIS与nano—CaCO3产生协同增韧效应,复合材料的无缺口冲击强度可提高到9．83kJ／m^2,但其缺口敏感性增大;SIS—MAH较SIS对PS／nano—CaCO3复合材料具有更好的增韧效果,接枝率为3．08％的SIS—MAH改性PS／CaCO3复合材料（质量比100／5／6）的无缺口冲击强度可提高到11．69kJ／m^2;当SIS用量为6份时,SIS改性复合材料不发生弯曲断裂;当SIS—MAH用量为2份时,SIS—MAH改性复合材料不发生弯曲断裂。     

高抗冲聚苯乙烯替代丙烯腈-丁二烯-苯乙烯的研究

采用不同含量的增韧剂对高抗冲聚苯乙烯(HIPS)材料进行改性,考察了改性后复合材料的性能变化及与丙烯腈-丁二烯-苯乙烯(ABS)材料的对比情况.研究表明:在一定的配方中,HIPS改性复合材料的流动性、韧性和耐候性均优于ABS材料的,对于部分领域的材料替代有较大实际意义.     

用于包覆丙烯腈-丁二烯-苯乙烯共聚物的苯乙烯嵌段共聚物热塑性弹性体的制备与性能

以苯乙烯-乙烯-丁烯-苯乙烯嵌段共聚物(SEBS)为基体,白油为增塑剂,热塑性聚氨酯(TPU)为极性改性剂,SEBS接枝马来酸酐(SEBS-g-MAH)为相容剂,利用双螺杆挤出机共混挤出制备了用于包覆丙烯腈-丁二烯-苯乙烯共聚物(ABS)的包覆料,考察了填料种类和TPU、白油及SEBS-g-MAH的用量对包覆料物理机械性能、黏结性能及微观相态的影响。结果表明,随着TPU用量的增加,SEBS包覆料的邵尔A硬度、拉伸强度和扯断伸长率均提高,且对ABS的剥离强度增大,综合考虑,TPU最佳用量为50份;在碳酸钙、滑石、云母和高岭土4种填料中,碳酸钙填充的SEBS包覆料对ABS的剥离强度最佳,滑石的效果最差;随着白油用量的增加,SEBS包覆料对ABS的剥离强度减小;加入SEBS-g-MAH后,SEBS包覆料的相界面不明显,趋向于形成连续相结构;随着SEBS-g-MAH用量的增加,包覆料对ABS的剥离强度先增大后减小,当SEBS-g-MAH用量为5份时,剥离强度达到最大值(2.5 k N/m)。     

Mechanical properties of polystyrene/ethylene-propylene copolymer blends

Some mechanical properties of blends of polystyrene (PS) and ethylene-propylene-rubber (EP) were derived from stress-strain and impact measurements. The strength and impact properties are improved by adding EP-g-PS graftcopolymer, prepared by reacting PS with EP, to the blends. It is assumed that the EP-g-PS graftcopolymer acts as an adhesive at the interface between the thermoplast and the rubber phases. The addition of the graftcopolymer reduces the dimensions of the dispersed rubber particles. High values of impact strength at reasonable values of tensile moduli could be reached by replacing EP for a smaller or larger part by EP-g-PS copolymer. These kinds of EP-modified PS blends had much higher impact values than those of comparable PS blends containing low density polyethylene (1 dPE) and 1dPE-g-PS graftcopolymer or this graftcopolymer only. It seems attractive to ascribe these results to the non-crystallinity of the PE-g-PS as compared with the crystallinity of 1dPE in 1dPE and in 1dPE-g-PS. However some caution seems recommendable as EP-modified PS fractures with microshear whereas, the PE-modified PS shows crazing.     

Effect of maleic anhydride grafted polybutadiene on the compatibility of polyamide 66/acrylonitrile‐butadiene‐styrene copolymer blend

The addition of maleic anhydride grafted polybutadiene (PB‐g‐MAH) can greatly improve the compatibility of polyamide 66 (PA66)/acrylonitrile‐butadiene‐styrene copolymer (ABS) blends. Unlike the commonly used compatibilizers in polyamide/ABS blends, PB‐g‐MAH is compatible with the ABS particles' core phase polybutadiene (PB), rather than the shell styrene‐acrylonitrile (SAN). The compatibility and interaction of the components in the blends were characterized by Fourier transform‐infrared spectra (FTIR), Molau tests, melt flow index (MFI), dynamic mechanical analyses (DMA), and scanning electron microscopic (SEM) observations. The results show that PB‐g‐MAH can react with the amino end groups in PA66 while entangle with the PB phase in ABS. In this way, the compatibilizer anchors at the interface of PA66/ABS blend. The morphology study of the fracture sections before and after tensile test reveals that the ABS particles were dispersed uniformly in the PA66 matrix and the interfacial adhesion between PA66 and ABS was increased significantly. The mechanical properties of the blends thus were enhanced with the improving of the compatibility. POLYM. ENG. SCI., 2012. © 2011 Society of Plastics Engineers     

Reactivity of acrylonitrile-butadiene-styrene terpolymer grafted with long-chain unsaturated carboxylic acids

Reactivity of acrylonitrile-butadiene-styrene terpolymer (ABS) grafted with long-chain carboxylic acids, such as undecylenic acid and oleic acid, was investigated and compared with that of ABS grafted with short-chain carboxylic acids by reacting with dodecylamine, glycidyl methacrylate (GMA), and 2-ethyl-2-oxazoline in solution, and with polyamide (PA) in melt. The overall activation energy of ABS-g-acrylic acid, ABS-g-crotonic acid, ABS-g-undecylenic acid and ABS-g-oleic acid reacting with dodecylamine was 31.2, 16.2, 18.2 and 21.6 kJ/mol, respectively. The overall activation energy of ABS-g-acrylic acid, ABS-g-crotonic acid, ABS-g-undecylenic acid and ABS-g-oleic acid reacting with GMA was 29.0, 31.9, 61.4 and 61.8 kJ/mol, respectively. The stronger the acidity of grafted acid, the higher the percentage of the grafted acid reacted. The overall activation energy of ABS-g-acrylic acid, ABS-g-crotonic acid, ABS-g-undecylenic acid and ABS-g-oleic acid reacting with 2-ethyl-2-oxazoline was 19.5, 20.9, 23.4 and 24.5 kJ/mol, respectively. The lower the steric hindrance and the higher the chain mobility of grafted acid, the higher the percentage of the grafted acid reacted. The reactivity of dodecylamine, GMA and 2-ethyl-2-oxazoline reacting with grafted ABS is: GMA<2-ethyl-2-oxazoline<dodecylamine. The reactivity of grafted polymer is: ABS-g-acrylic acid<ABS-g-crotonic acid<ABS-g-oleic acid<ABS-g-undecylenic acid, when they react with PA in melt.     

顺酐化聚苯乙烯对PVC/SEBS共混物的增容作用

以顺酐化聚苯乙烯(PS-g-MAH)为增容剂,研究了苯乙烯-乙烯-丁烯-苯乙烯嵌段共聚物(SEBS)对聚氯乙烯(PVC)的共混增韧改性,讨论了该共混物在常温、低温下的力学性能及动态力学性能。结果表明,PS-g-MAH能明显改善SEBS与PVC的相容性,使PVC/SEBS共混物中分散相颗粒尺寸明显减小,分布更均匀,共混物的玻璃化转变温度内移,常温和低温下缺口冲击强度增大。当PVC/PS-g-MAH/SEBS(质量比)为75/6/25时,共混物的常温缺口冲击强度为50.6 kJ/m2,低温(-20℃)缺口冲击强度为29.8 kJ/m2。     

Temperature dependence of tack and pulse NMR analysis of polystyrene block copolymer/tackifier system

The influence of tackifier structure on the temperature dependence of tack for a polystyrene block copolymer/tackifier system was investigated. A blend of polystyrene-block-polyisoprene-block- polystyrene triblock and polystyrene-block-polyisoprene diblock copolymers was used as the base polymer. Four different tackifiers were used: special rosin ester resin (RE), rosin phenolic resin (RP), hydrogenated cyclo-aliphatic resin (HC), and aliphatic petroleum resin (C5). Tack at 20?°C increased with the tackifier content for both RE and HC tackifier systems. Tack is affected by two factors: the work of adhesion at the adherend interface and the viscoelastic properties of the adhesive. The good balance of these two factors brought high tack. The adhesive with 10 wt.% tackifier exhibited the highest tack at 20?°C, whereas those with 30 and 50 wt.% tackifier were lower than those systems with 10 wt.% of the RP or C5 tackifiers. The adhesive with overly high hardness lowered the work of adhesion and the tack was not improved with more than 30 wt.%. A compatibility test in toluene solution and in solid state showed that tackifier RE has good compatibility with both polyisoprene and polystyrene, whereas tackifier RP has lower compatibility. Tackifiers HC and C5 had good compatibility with polyisoprene, but poor compatibility with polystyrene, and that of C5 was poorer. Pulse nuclear magnetic resonance (NMR) analyses indicated that tackifiers RE and HC effectively restrict the molecular mobility of polyisoprene phase.     

The study of polystyrene blends: The relationship of phases and structure in blends of polystyrene with ethylene–propylene diene monomer rubber and its grafted copolymer

Pressed films of blends of polystyrene (PS) with ethylene–propylene diene monomer rubber (EPDM) or grafted copolymer of styrene (St) onto EPDM (EPDM-g-St) rubber were examined by small-angle X-ray scattering (SAXS), and scanning electron microscope (SEM). Small-angle X-ray scattering from the relation of phase was analyzed using Porod's Law and led to value of interface layer on blends. The thickness of interface layer (σ_b) had a maximum value at 50/50 (PS–EPDM-g-St) on blends. The radius of gyration of dispersed phase (domain) and correlation distances a_c in blends of PS–EPDM-g-St were calculated using the data of SAXS. The morphology and structure of blends were investigated by SEM. © 1998 John Wiley & Sons, Inc. J. Appl. Polym. Sci. 70: 805–810, 1998     

Thermal conductivities of blends of polyethylene/SEBS block copolymer and polystyrene/SEBS block copolymer

Thermal conductivities of two series of blends of polystyrene and styrene–ethylene/butyrene–styrene block copolymer (PS/SEBS), and polyethylene and styrene-ethylene/butylene-styrene block copolymer (PE/SEBS) were measured. Here the PS part and hydrogenated polybutadiene (EB; ethylene-butene-1 copolymer) part of SEBS were confirmed to be miscible in PS and PE homopolymers, respectively, by the differential scanning calorimetry. The thermal conductivity of PS/SEBS increased, while that of PE/SEBS blends decreased monotonically, with increasing SEBS content. No significant changes in the range where microphases usually occur were noted. The thermal conductivities of PS/SEBS and PE/SEBS were explained by modifications of our equation for composites. Thermal conductivity of EB in SEBS was estimated from that of PS/SEBS blend as 4.9 × 10^?4 cal/s cm °C. Further, the thermal conductivity of PE/SEBS could be predicted by substituting the obtained value of EB into the modified equation. Therefore, the modified equations were confirmed to be applicable to thermal conductivities of PE/SEBS and PE/SEBS blends. © 1993 John Wiley & Sons, Inc.     

Structural changes in the grafted copolymer polyethylene-styrene

The general method for phase analysis was used on X-ray diffractograms of copolymers produced by the direct and the indirect method of grafting styrene to polyethylene. It was established that both copolymer systems show small deviations from a two-phase structure. Up to a polyethylene to polystyrene ratio of 1:1 the grafting process did not cause any substantial change in crystalline structure. Crystallites were not destroyed in either system. The main structural changes resulting from grafting appeared in disordered regions of polyethylene. The diffraction curves determined for individual structural states are discussed and used as a basis to construct structural models.     

Compatibility of waste rubber powder/polystyrene blends by the addition of styrene grafted styrene butadiene rubber copolymer: effect on morphology and properties

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 (T _g) 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 T _g 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 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.     

Dependence of thin polystyrene films stability on the thickness of grafted polystyrene brushes

We investigate the stability of thin polystyrene (PS) films on chemically identical grafted brushes of various thickness and grafting density. We observe an essential influence of the brush thickness on the stability of the PS films. For brushes with a thickness of 20-35 nm no de-wetting of the PS film occurs, while considerably thicker or thinner PS brushes lead to de-wetting of the PS top layer. We suggest that in the thin brush-like layers, the unfavorable interactions with underlying silica favor de-wetting. The tendency to de-wet is reduced once the brush is sufficiently thick to insulate the free PS layer from the surface. Beyond that point, the de-wetting process speeds up as the brush becomes thicker and has a higher grafting density with a substantial increase of the interfacial tension between the brush and the free polymer.     

丙烯腈-丁二烯-苯乙烯树脂改性用丁苯嵌段共聚物的合成

以正丁基锂为引发剂、环己烷为溶剂、四氢呋喃为调节剂,在模试装置上合成了丙烯腈-丁二烯-苯乙烯(ABS)树脂改性用橡胶——丁苯嵌段共聚物,研究了反应温度与产品支化结构含量、相对分子质量与产品门尼黏度、凝胶质量分数、微观结构含量的关系。结果表明,随着聚合反应最高温度的升高,共聚物支化结构含量增大;当引发温度为55℃、反应最高温度为110～120℃时,产品支化结构含量约为5%,分子量分布约为1.12,其凝胶质量分数、微观结构含量与目标产品一致,丁苯嵌段共聚物的各项性能实测值符合ABS树脂改性用胶要求。     

Glass transition behavior of polypropylene/polystyrene/styrene-ethylene-propylene block copolymer blends

Summary The glass transition behavior of ternary blends of polypropylene (PP), polystyrene (PS) and styrene-ethylene-propylene-styrene block copolymer (SEPS) was investigated. The blends were prepared by an internal mixer, and their dynamic mechanical properties and morphology were measured. The blends showed phase inversion at around 75wt% PS composition. The glass transition temperature (T_g) of the PP phase shifted to lower temperature as the PS contents were increased in PP/PS binary blends, probably due to the mismatch of thermal expansion coefficients between two components. As the SEPS copolymer contents were increased, the T_g's of the PP phase in the blends increased. In particular, the large increase in T_g of the PP phase was observed in the PP/PS (25/75) blends where the phase inversion takes place. Received: 2 February 1998/Revised version: 24 March 1998/Accepted: 13 April 1998