尼龙11/MBS/环氧树脂共混合金的力学性能和增韧机理

对尼龙11共混合金体系的力学性能进行了考察,对于尼龙11／EXL－2691核－壳冲击改性剂／相容剂三元共混合金体系加入环氧树脂后,分散相0冲击改性剂在尼龙11基体中的分布更加均匀,两相的相容性提高,但分散相粒子粒径并未随环氧树脂用量的增加而减小,加入1％的环氧树脂后,共混合金体系冲击强度最大,分散相粒子粒径最小,体系的断裂强度随着环氧树脂用量的增加而增大,伸长率则降低,此共混合金体系的增韧机理为分散相引发银纹机理。     

尼龙结构对尼龙/聚乙烯共混物织构形态的影响

比较了尼龙６／线型低密度聚乙烯（ＰＡ６／ＬＤＰＥ）和尼龙１０１０／线型低密度聚乙烯（ＰＡ１０１０／ＬＬＤＰＥ）共混和的织构形态,共混物的织构形态除与织构调节剂、组分比有关外,还与尼龙物结构有很大关系。在尼龙／聚乙烯二元共混物中,分散相粒子以球状（或椭球状）形式存在,粒子较大,两相界面清晰,加入织构调节剂后,分散相粒子明显变小,分布均匀,在尼龙６共混物中,除仍有表面光滑的球状粒子外,出现了莲藕断面状粒子,但两相之间仍有缝隙,而在尼龙１０１０共混物中,出现了辐（车）轮状粒子,两相间相互作用强,分散相粒子与连续相之间紧紧地连接在一起,表明高碳数的尼龙１０１０与聚乙烯的链段间的相容性更好。     

PIB／EPDM共混体系辐射效应的研究

考察了PIB/EPDM共混体系的辐射效应,以及体系的相容性、相态对辐射效应的影响。发现PIB在该共混体系中发生了辐射效应由裂解到交联的转变,并且在PIB的相态由连续相到分散相的转变区域交联的程度最大。共混体系的交联规律符合描述单一组分线性聚合物辐射交联规津的基本关系式。     

相容剂甲基丙烯酸缩水甘油酯对尼龙6/SEBS-g-MA/蒙脱土复合材料的性能影响及机理

以马来酸酐接枝SEBS(SEBS-g-MA)和有机蒙脱土(OMMT)分别作增韧剂和增强填料,甲基丙烯酸缩水甘油酯(GMA)为相容剂,采用熔融挤出方法制备了尼龙6/SEBS-g-MA/OMMT复合材料。通过扫描电镜(SEM)、力学性能测试、Molau实验及红外光谱(FT-IR)表征,考察了SEBS-g-MA、OMMT和GMA对复合材料的相形态和力学性能的影响。结果表明,OMMT能弱化PA6和SEBS-g-MA之间的相互作用力,导致橡胶相粒径增大,冲击强度降低。而GMA的使用,使PA6、SEBS-g-MA和GMA间形成化学反应,提高PA6和SEBS-g-MA之间的相容性,改善SEBS-g-MA的分散质量,减小分散相颗粒尺寸,进一步提高共混物的冲击强度。GMA存在时制备的复合材料可以获得具有良好平衡的综合力学性能。     

马来酸酐接枝SEBS对尼龙6/SEBS共混物聚集态结构的影响

研究了马来酸酐(MAH)接枝的部分氢化苯乙烯-丁二烯-苯乙烯三嵌段共聚物(SEBS)(SEBS-g—MAH)对尼龙6／SEBS的共混物聚集态结构的影响。研究结果表明,SEBS—g—MAH上的MAH侧基和尼龙6的端氨基发生了缩合反应,增加了尼龙6和SEBS的界面相互作用．透射电镜(TEM)的结果表明,当SEBS在尼龙6／SEBS共混物中为分散相时,SEBS-g—MAH使得分散相颗粒尺寸明显减小,两相界面变得模糊．示差扫描量热仪(DSC)的研究结果表明,SEBS-g—MAH的引入对尼龙6／SEBS共混物的熔融峰、结晶峰和结晶度都有明显的影响．因此SEBS-g—MAH与SEBS相比能更有效地与尼龙6相容,在很大程度上改变了尼龙6／SEBS共混体系的聚集态结构。     

尼龙6/聚苯乙烯共混物融合缝的形态及其对力学性能的影响

采用扫描电镜(SEM)、力学性能测定,研究了尼龙6／聚苯乙烯(PA-6／PS)共混体系融合缝的形态及力学性能．鲒果表明,分散相和连续相的粘度比对融合缝的形态有重要影响．当η分散相／η连续相＞1时,融合缝处分散相的形态不同于本体．融合缝处分散相沿融合缝取向;当η分散相／η连续相＜1时．融合缝处分散相的形态与本体形态相似．均以球形粒子分散于基体中。融合缝的存在使共混体系的力学性能有较大下降,主要由融合缝处分散相形态所致。     

非对称嵌段共聚物PI-b-PB对IR/BR并用胶相形态与性能的影响

主要研究非对称嵌段共聚物PI-b-PB(液体橡胶LIR-390)对异戊橡胶/顺丁橡胶(IR/BR)共混体系相形态、加工性能和力学性能的影响。采用原子力显微镜(AFM)表征IR/BR并用胶的相形态,结果显示,LIR-390能够细化分散相(BR)的尺寸,且使分散相分布更加均匀;但加入过量LIR-390(7份)则会减弱其增容作用,使BR的相尺寸增大。通过哈克旋转流变仪测试IR/BR未硫化胶的流变特征,发现LIR-390能够降低未硫化胶的储能模量(G′),得出在橡胶共混过程中加入LIR-390可以减少加工能耗。利用裂纹生长测试平台分析并用胶的抗疲劳裂纹生长性能,结果表明,LIR-390的增容作用有助于减小分散相的尺寸,从而降低裂纹生长速率;而加入过量LIR-390则会致使开裂加快。     

增容作用和动态固化对聚丙烯/环氧树脂共混物形态结构的影响

研究了增容作用和动态固化对聚丙烯(PP)/环氧树脂(EP)共混物形态结构的影响。实验结果表明,PP/EP共混物是不相容共混体系,当环氧树脂含量小于50%时,共混物中环氧树脂以分散相存在,PP为连续相。反之,则共混物的相态发生相反转,即环氧树脂为连续相,PP为分散相。加入马来酸酐接枝聚丙烯(M AH-g-PP)促进环氧树脂与PP的相容性,使得分散相的颗粒明显变小。与PP/EP和PP/M AH-g-PP/EP共混物不同,当环氧树脂含量大于50%时,动态固化PP/EP和PP/M AH-g-PP/EP共混物仍是环氧树脂分散相和PP连续相结构,未出现相反转。对于相同含量环氧树脂的共混物,动态固化PP/M AH-g-PP/EP共混物中环氧树脂分散相尺寸明显小于动态固化PP/EP共混物中环氧树脂分散相尺寸。     

PET/EVA共混物的制备及其相容性的研究

对不同比例的PET和EVA组分进行共混 ,在理论上分析其相容性 ,并对所得样品用DSC进行热分析 ,用SEM观察其相结构。结果表明 ,PET/EVA共混体系在理论上属于热力学不相容体系 ,电镜照片显示PET和EVA呈海岛结构 ,PET为连续相 ,EVA为分散相。     

非对称嵌段共聚物PI-b-PB对IR/BR并用胶相形态与性能的影响

主要研究非对称嵌段共聚物PI-b-PB(液体橡胶LIR-390)对异戊橡胶/顺丁橡胶(IR/BR)共混体系相形态、加工性能和力学性能的影响.采用原子力显微镜(AFM)表征IR/BR并用胶的相形态,结果显示,LIR-390能够细化分散相(BR)的尺寸,且使分散相分布更加均匀;但加入过量LIR-390(7份)则会减弱其增容作用,使BR的相尺寸增大.通过哈克旋转流变仪测试IR/BR未硫化胶的流变特征,发现LIR-390能够降低未硫化胶的储能模量(G7),得出在橡胶共混过程中加入LIR-390可以减少加工能耗.利用裂纹生长测试平台分析并用胶的抗疲劳裂纹生长性能,结果表明,LIR-390的增容作用有助于减小分散相的尺寸,从而降低裂纹生长速率;而加入过量LIR-390则会致使开裂加快.     

Carbon black–clay hybrid nanocomposites based upon EPDM elastomer

The present study explored the effect of nanoclay on the properties of the ethylene–propylene–diene rubber (EPDM)/carbon black (CB) composites. The nanocomposites were prepared with 40 wt% loading of fillers, where the nanoclay percentage was kept constant at 3 wt%. As the modified nanoclay contains the polar groups and the EPDM matrix is nonpolar, a polar rubber oil extended carboxylated styrene butadiene rubber (XSBR), was used during the preparation of nanocomposites to improve the compatibility. Primarily the nanoclay was dispersed in XSBR by solution mixing followed by ultrasonication. After that EPDM-based, CB–clay hybrid nanocomposites, were prepared in a laboratory scale two roll mill. The dispersion of the different nanoclay in the EPDM matrix was observed by wide-angle X-ray diffraction (WAXD) and high resolution transmission electron microscopy. It was found that the mechanical properties of the hybrid nanocomposites were highly influenced by the dispersion and exfoliation of the nanoclays in the EPDM matrix. Thermo gravimetric analysis, scanning electron microscopy and dynamic mechanical thermal analysis was carried out for each nanocomposite. Among all the nanocomposites studied, the thermal and mechanical properties of Cloisite 30B filled EPDM/CB nanocomposite were found to be highest.     

Novel approach for the selective dispersion of MWCNTs in the Nylon/SAN blend system

Multiwalled carbon nanotubes (MWCNTs) were coated with TiO₂ by sol gel process. The coating was confirmed by TEM, XPS and XRD. TEM analysis showed that rough coating was formed on the MWCNTs. These modified MWCNTs and pristine MWCNTs were dispersed in the blend of nylon 66 and SAN by melt blending. FESEM images showed that pristine MWCNTs were preferably dispersed in the nylon phase whereas TiO₂ modified MWCNTs confined to the SAN phase. The selective dispersion was explained on the basis of migration and stabilization of these high aspect ratio nanotubes in the Nylon/SAN blend system. The hydrogen bonding interaction between the CN group of SAN and surface hydroxyl group of TiO₂ coated MWCNTs has restricted the migration of modified MWCNTs from SAN to nylon phase.     

Effect of crosslinking on morphology and phase inversion of EPDM/PP blends

This study investigates the effect of cross-linking on morphology and phase inversion of EPDM/PP blends. Several EPDM/PP blends without and with cross-linking agent were prepared in a Haake batch mixer under constant conditions. The morphology was studied by electronic microscopy (SEM and TEM), and cross-linking was followed by EPDM gel content and swelling. The results showed that the position of the phase inversion region is essentially governed by composition, being independent of the viscosity ratio of the EPDM/PP blend. The TPVs’ morphology of the EPDM/PP blend, with 70 and 50 wt% of PP, consists of EPDM cross-linked particles dispersed in the PP matrix. For EPDM-rich composition (30 wt% of PP), the TPVs’ morphology appears to be co-continuous. Even though dynamic vulcanisation of the rubber phase always improves the dispersion of the EPDM phase, complete phase inversion (from fully dispersed PP in the EPDM matrix to EPDM fully dispersed in the PP matrix) was achieved only with low viscosity EPDM.     

The role of tackifiers on the auto-adhesion behavior of EPDM rubber

The article describes the effect of hydrocarbon (HC) and coumarone-indene (CI) resin tackifiers on autohesion behavior of ethylene propylene diene polymethylene (EPDM) rubber. The viscoelastic behavior and nature of compatibility of EPDM/tackifier blends were studied by means of dynamic mechanical analysis. Furthermore, scanning electron microscopy and atomic force microscopy were used to understand the compatibility of the EPDM/tackifier blends. The HC tackifying resin modified the viscoelastic properties of the EPDM rubber in such a way that it behaved as a plasticizer at lower frequency by reducing the storage modulus and filler at higher frequency by increasing the storage modulus. On the contrary, the CI modified EPDM rubber did not show similar behavior; the modulus enhanced throughout the entire frequency range. The viscosity of the matrix was found to be highly governed by the compatibility as well as amount of tackifier present in the blend. In order to explain the tack behavior, several tack governing factors such as green strength, creep compliance, entanglement molecular weight, relaxation time, self-diffusion coefficient, and monomer friction coefficient (ζ₀) were investigated. The tack strength increased with HC tackifier loading up to 24 parts per hundred grams of rubber (phr), beyond which a plateau region was observed. A maximum of 196% improvement was observed at 24 phr HC loaded sample as compared to gum EPDM rubber devoid of tackifier. Conversely, there was a marginal improvement of tack strength (36%) up to 8 phr loading for the system containing CI, beyond which it dropped.     

Fracture resistance of polyblends and polyblend matrix composites Part III Role of rubber type and location in nylon 6,6/SAN composites

The role of rubber particle type, location and morphology on toughening in blends of nylon 6,6 with styrene acrylonitrile (SAN), with and without fibre reinforcements was examined in this study. The rubber used was ethylene propylene diene monomer (EPDM) rubber and the results were compared to a previous study that used butadiene rubber. The compositions of the blends ranged from pure nylon 6,6 to pure SAN. EPDM rubber was chemically compatibilized with one of the matrix phases rather than grafted, as in the ABS. In order to study the effect of rubber location on fracture behaviour, the approach was to compatibilize EPDM with either the minor phase or the major phase component of the blend. Attention was focused on fracture initiation toughness and fracture propagation toughness, measured through the parameters J _IC and J _SS, respectively. J _SS refers to the steady-state, or plateau value of the material R-curve and was therefore a measure of total toughness which included the additional component derived from crack extension. The results indicated that EPDM rubber was not as effective a toughening agent as was butadiene in the Acrylonitrile Butadiene Styrene (ABS) system, primarily due to the morphology of EPDM and its interface character with the nylon 6,6 or SAN matrix. It was demonstrated that the embrittlement effects of a second rigid polymer phase can be mitigated by selectively adding rubber to that phase in the alloy or blend. With regard to the role of fibre reinforcement, a strong fibre matrix interface was found to be essential for toughening. Further, the extent of rubber toughening was larger when fibres were present than when fibres were absent, provided the fibre matrix interface was strong. Fibres also, like rubber, enhanced local matrix plasticity as well as reduced the embrittlement effects associated with a second polymer phase.     

PP三元共混合金的力学性能及结晶行为研究

研究了不同乙烯含量的ＥＰＤＭ对ＰＰ／ＵＨＭＷＰＥ合金的增容作用,并讨论了共混体系结晶行为的变化情况。发现ＥＰＤＭ中乙烯含量的增加可提高增容效果;在ＰＰ／ＵＨＭＷＰＥ／ＥＰＤＭ为１００／１０／６时,共混物缺口冲击强度可达９１．１ｋＪ／ｍ＾２,为ＰＰ的３．５倍,此时拉伸强度仍比纯ＰＰ高４．３ＭＰａ。     

Highly toughened polypropylene/ethylene–propylene-diene monomer/zinc dimethacrylate ternary blends prepared via peroxide-induced dynamic vulcanization

Polypropylene (PP)/ethylene–propylene-diene monomer (EPDM)/zinc dimethacrylate (ZDMA) blends with remarkable toughness and extensibility were successfully prepared via peroxide dynamical vulcanization. A unique structure with the EPDM particles surrounded by a transition zone containing numerous polymerized ZDMA (PZDMA) nano-particles was observed for the first time by using transmission electron microscopy (TEM) examination, which contributed to the dramatically increase of Izod impact strength. Dynamic mechanical analysis (DMA) confirmed that the possible PZDMA graft products resulted from peroxide dynamical vulcanization improved the compatibility between EPDM and PP phases. The specific morphology of the PP/EPDM/ZDMA blends indicated that ZDMA can lead to size reduction and good distribution uniformity of the crosslinked rubber particles and the increase of adhesion between PP matrix and EPDM phases during deformation. The synergic effect of the increase in the effective volume of the EPDM phase, the improved compatibility and adhesion between EPDM and PP phases and the deformation of those fine rubber particles is believed to result in the remarkable high toughness and extensibility of the PP/EPDM/ZDMA blends. Particularly for the PP/EPDM ratio of 70/30, the PP/EPDM/ZDMA (70/30/9, w/w/w) ternary blends with the Izod impact strength nearly 2 times higher than PP/EPDM (70/30, w/w) binary blends and 15–20 times higher than PP are achieved; besides, the elongation at break of PP/EPDM/ZDMA ternary blends is 4–5 times higher than that of PP/EPDM binary blends.     

HDPE/MPA共混物层状结构及阻隔性能研究

将少量对烃类溶剂具有高效阻作用的阻隔性树脂－改性尼龙与高密度聚乙烯共混,通过对共混工艺条件和分散相ＭＰＡ形态的控制,可获得具有高阻性能的ＨＤＰＥ／ＭＰＡ共混材料。     

IPP／Zn—SEPDM共混物的DMA和SAXS研究

本文通过SAXS、DMA和TEM研究了乙丙三元橡胶(EPDM)和乙丙橡胶磺酸锌盐(Zn-SEPDM)对等规聚丙烯(IPP)晶体结构的影响以及IPP/Zn-SEPDM和IPP/EPDM共混物的相容性。用一维电子密度函数分别求得IPP晶区、非晶区和聚丙烯晶相和非晶过渡层厚度,用虚拟两相模型描述了IPP的晶体结构。EPDM和Zn-SEPDM与IPP的非晶相和过渡相均有一定相互作用,随磺化度提高,相互作用增强。由于在乙丙橡胶分子链中引入了磺酸锌盐基团,离子基团聚集成离子微区,形成物理交联点,抑制了共混物的相分离,提高了制品的韧性和强度。