硬沥青改性聚丙烯材料的研究

采用熔融共混方法,用高软化点硬沥青对聚丙烯进行改性。力学测试表明:硬沥青的加入使聚丙烯的冲击强度得到大幅度提高,但拉伸强度有一定程度下降;DSC测试表明:硬沥青的加入使PP的结晶度下降;扫描电镜微观证实,均匀分散的硬沥青使聚丙烯从脆性材料过渡到韧性材料,这是聚丙烯材料冲击强度提高的原因。     

端羧基聚苯乙烯的合成及其应用

以巯基乙酸为链转移剂,通过本体聚合得到低相对分子质量含端羧基的聚苯乙烯(PSCOOH),并将其用作聚苯乙烯(PS)/纳米CaCO3复合材料的分散改性剂。在链转移剂作用下可获得数均分子量约为850的PSCOOH。随着PSCOOH相对分子质量的减小,用它分散改性的PS/纳米CaCO3复合材料的拉伸强度提高,其中PSCOOH-4改性复合材料的拉伸强度提高了约15％,缺口及无缺口冲击强度略有下降。低相对分子质量分散剂有较好的增强作用。     

核壳改性剂增韧聚苯醚/聚苯乙烯共混物的形态结构及性能

采用乳液聚合方法合成了核壳比为50/50(聚丁二烯/聚苯乙烯,PB/PS),粒径分别为120 nm和350 nm的PB-g-PS接枝共聚物,而后将PB-g-PS弹性体与高抗冲聚苯乙烯(HIPS)同时作为改性剂增韧聚苯醚(PPO)/聚苯乙烯(PS)共混物,考察了基体组成(PPO/PS)和橡胶粒子尺寸对HIPS/PPO/PS/PB-g-PS共混物的力学性能及形态结构的影响。结果表明,随着基体中PPO含量的增加,共混物的冲击强度和拉伸屈服强度显著提高。HIPS中Salami结构橡胶粒子和亚微米尺寸橡胶粒子在PPO/PS基体中分散状态较好,协同增强了共混物的韧性;随着PB-gPS橡胶粒子尺寸的增加,共混物的冲击强度逐渐增加而拉伸屈服强度无明显变化,同时共混物的冲击断裂方式逐渐由脆性断裂向韧性断裂发生转变。     

一步原位气泡拉伸法制备LDHs/PS纳米复合材料及其力学性能分析

采用一步原位气泡拉伸(ISBS)法制备了水滑石/聚苯乙烯(LDHs/PS)纳米复合材料,研究了ISBS对LHDs的分散情况和复合材料机械性能的影响。结果表明:与双螺杆机械分散法相比,ISBS法可以实现LDHs在PS中纳米级均匀分散;通过双螺杆挤出机消泡处理后,分散开的LDHs没有发生明显的再团聚;相同添加量情况下,一步ISBS法制备的复合材料具有更好的机械性能,在一定添加量范围内,材料的冲击强度和拉伸强度随着添加量的增大而增大,均在LDHs质量分数为5%时达到最大值。     

超支化聚磷酸酯/聚苯乙烯复合材料的性能研究

以密炼、模压等工艺制备了超支化聚磷酸酯(HPPE)/聚苯乙烯(PS)复合材料,研究了HPPE的代数和用量对HPPE/PS复合材料性能的影响及其规律性,研究的性能包括拉伸强度、弯曲强度、冲击强度、维卡软化点温度以及熔体质量流动速率,并通过SEM观察其冲击断面的微观形态和研究其增韧机理.结果表明:HPPE/PS复合材料的拉伸强度、冲击强度和熔体质量流动速率随HPPE用量的增加先增加后降低,随HPPE摩尔质量的变化影响较小.在HPPE-2用量为6 phr左右,复合材料的综合性能较佳,对比纯PS,拉伸强度可提高124%,冲击强度可提高56%,熔体质量流动速率可提高84%,但弯曲强度和维卡软化点温度有微弱下降.     

POE-g-MAH对PP/PS合金形态结构和力学性能的影响

采用双螺杆挤出机反应挤出法制备了马来酸酐接枝乙烯-1-辛烯共聚物(POE-g-MAH)。研究了聚苯乙烯(PS)和POE-g-MAH对聚丙烯(PP)/PS合金形态结构和力学性能的影响。结果表明:PS能提高PP/PS合金的拉伸强度和弯曲强度,同时降低了其冲击强度;在PP/PS合金中加入少于5份的POE-g-MAH,不仅能够显著改善PP/PS合金的相容性,明显降低分散相的粒径,而且能够使PP/PS合金在保持较高的拉伸强度和弹性模量的同时,大幅度提高其冲击强度。     

CaCO_3对SBS/PS共混体系的增强增韧研究

采用熔融共混法制备了丁苯热塑性弹性体(SBS)/聚苯乙烯(PS)共混材料,研究了CaCO3对SBS/PS共混物拉伸性能、弯曲性能、冲击性能和耐热性能的影响。结果表明:CaCO3用量的增加,对SBS/PS共混物拉伸强度的影响不大,而断裂应变有所提高;SBS/PS共混物弯曲模量、弯曲强度、定挠应力和弯曲破坏应力呈现先下降后上升的趋势,且均比未添加CaCO3时有较大幅度提升;SBS/PS共混物的冲击强度和维卡软化温度也随着CaCO3用量的增加而提高。     

EDA-GO/CPE/PS纳米复合材料的制备及性能研究

选取氯化聚乙烯(CPE)弹性体为增韧剂,乙二胺接枝氧化石墨烯(EDA-GO)为纳米填料,经熔融共混法制备了CPE/聚苯乙烯树脂(PS)和EDA-GO/CPE/PS纳米复合材料。采用红外光谱、拉伸测试、冲击测试和熔融指数测试方法研究了EDA-GO的表面结构,复合材料的拉伸性能、冲击性能和熔融流动性能。结果表明,乙二胺(EDA)已成功接枝于氧化石墨烯(GO)的表面上;在CPE/PS复合材料中,材料的拉伸强度和冲击强度的变化规律与一般弹性体增韧塑料的规律一致;在EDA-GO/CPE/PS纳米复合材料中,随着EDA-GO含量的增加其拉伸强度、冲击强度、断裂伸长率和弹性模量都有先上升后下降的趋势,当EDA-GO质量分数为0.5%时,拉伸强度达最大值,较CPE/PS复合材料提高了38%,较纯PS提高了61%;在EDA-GO质量分数为0.75%时,其冲击强度和弹性模量最大,比CPE/PS复合材料冲击强度和弹性模量分别提高了18%和41%。因此,当EDA-GO的质量分数在0.5%~0.75%之间时,复合材料的综合力学性能最好。随着EDA-GO的加入,纳米复合材料的熔融指数先下降后上升。     

PS/弹性体/Nano-TiO_2复合材料形态及力学性能

采用熔融共混法制备PS/弹性体/nano-TiO2复合材料,利用扫描电子显微镜(SEM)观察材料刻蚀断面和冲击断面的形貌,电子万能拉伸试验机及组合冲击试验机分别表征材料的拉伸和冲击性能,研究对比PS/SEBS/nanoTiO2和PS/SEBS-g-MAH/nano-TiO2复合材料的形态及力学性能。结果表明:PS/SEBS/nano-TiO2复合材料刻蚀断面的分散相SEBS粒径在0.6~1.4μm之间,而PS/SEBS-g-MAH/nano-TiO2复合材料分散相SEBS-g-MAH粒径显著减小,在0.5μm以下。与PS/SEBS/nano-TiO2复合材料相比,PS/SEBS-g-MAH/nano-TiO2复合材料的拉伸强度降低幅度减弱,在弹性体质量分数为16%时缺口冲击强度提高20%。复合材料冲击断面显示SEBS-g-MAH粒子比SEBS粒子更细微、更均匀地分散在PS基体中。     

相容剂对PP／PS形态与力学性能的影响

研究了苯乙烯-乙烯／T-烯-苯乙烯共聚物（SEBS）、聚丙烯与苯乙烯接枝共聚物（PP—g-PS）、沙林（Surlyn）对聚丙烯／聚苯乙烯（PP／PS）形态和力学性能的影响。结果表明：SEBS对PP／PS的冲击强度有比较明显的提高，但拉伸强度有所下降；PP-g-PS使PP／PS相界面变得模糊，分散相微粒尺寸变小，分布变窄，PP／PS相容性得到改善；Surlyn使PP／PS力学性能略微下降，增容作用不显著。     

针状硅灰石对阻燃HIPS材料性能和形态的影响

通过在阻燃高抗冲聚苯乙烯(HIPS)材料中加入不同用量的针状硅灰石的试验研究,发现一定用量的硅灰石可提高阻燃HIPS材料的断裂伸长率、弯曲弹性模量、耐热性和加工性能,而对阻燃HIPS材料的拉伸强度、冲击韧性和阻燃性能基本上无影响。扫描电子显微镜观察显示,硅灰石以一定长度的针状细条嵌入HIPS基体中,起到部分玻璃纤维的改性作用,阻燃HIPS材料的冲击断面仍为韧性断裂。     

Mechanical Properties and Morphology of Nitrile Rubber Toughened Polystyrene

Mechanical properties and morphology of blends of polystyrene and finely powdered (uncrosslinked and crosslinked) nitrile rubber were studied with special reference to the effect of blend ratio. Blends were prepared by melt mixing polystyrene and nitrile rubber in an internal mixer at 180°C in the composition range of 0–20 wt% nitrile rubber. The tensile stress/strain properties and impact strength of the polystyrene/nitrile rubber blends were determined using injection molded test specimens. In comparison to the blends with uncrosslinked nitrile rubber, blends with crosslinked nitrile rubber showed higher tensile strength, elongation at break, Young's modulus, impact strength, flexural strength, and flexural modulus. The enhanced adhesion between the dispersed nitrile rubber phase and the polystyrene matrix results in an increase in mechanical properties. Scanning electron micrographs of the fractured surfaces confirm the enhancement in mechanical properties.     

活性增容剂对环氧沥青性能影响的研究

采用活性增容剂、固化剂、基质沥青和环氧树脂熔融共混,制备得到一种环氧沥青,研究讨论了增容剂用量对沥青和环氧树脂相容性、环氧沥青固化体系撕裂断面、低温收缩率、对钢板的粘结强度以及拉伸强度的影响.研究发现,增容剂可以将沥青以5μm大小的球状有效分散在环氧树脂中.随着增容剂含量的增加,材料低温收缩率有所增加,对钢板的粘结强度...     

聚苯乙烯增强室温硫化硅橡胶的制备及表征

以过氧化苯甲酰为引发剂,使苯乙烯在α,ω-羟基聚(二甲基-甲基乙烯基)硅氧烷(PDM-MVS)中进行自由基聚合,制备了PDM-MVS/聚苯乙烯(PS)共混物。将该共混物在室温下进行硫化,获得了PS增强的室温硫化硅橡胶,并对硅橡胶的力学性能和微观形态进行了表征。结果表明,目标硅橡胶的拉伸强度和扯断伸长率均随PDM-MVS中乙烯基质量分数的增加而增大,当乙烯基质量分数为1.50%时,其拉伸强度达3.9 MPa,扯断伸长率达416%,PS的增强效果明显;目标硅橡胶具有微相分离结构,PS作为分散相均匀分布于PDM-MVS连续相中,两相的相容性随着PDM-MVS中乙烯基质量分数的增加而增强。     

Influence of poly(ethylene glycol)/montmorillonite hybrids on the rheological behaviors and mechanical properties of polypropylene

The effects of poly(ethylene glycol) (PEG)/montmorillonite (MMT) hybrids on the phase morphology, rheological behaviors and mechanical properties of polypropylene (PP) were investigated. The analysis of transmission electron microscopy (TEM) and wide-angle X-ray diffraction (WAXD) indicated that the PEG modified montmorillonite was intercalated and well dispersed into PP matrix. It was found that the addition of the PEG/MMT hybrids in PP matrix lead to a significant reduction of melt viscosity and enhancement in izod-notched impact strength and elongation at break, except that the tensile strength was without much obvious change. A quantitative analysis indicated that MMT was intercalated by PEG, which was responsible for the melt viscosity reduction of PP matrix. Differential scanning calorimetry (DSC) analysis indicated that the addition of PEG/MMT hybrids induced the formation of β-crystal of PP. Polarized light micrographs (PLM) analysis indicated that the dispersed MMT, which acted as a nucleating agent, lowered the spherulite dimension and increased the spherulite number, resulting in high izod-notched impact strength and elongation at break.     

Effects of thermoplastic poly(ether-ester) elastomer and bentonite nanoclay on properties of poly(lactic acid)

This work presented the influence of thermoplastic poly(ether-ester) elastomer (TPEE) and bentonite (BTN) on improving the mechanical and thermal properties of poly(lactic acid) (PLA). PLA was initially melt mixed with TPEE at six different loadings (5–30 wt%) on a twin screw extruder and then injection molded. The mechanical tests revealed an increasing impact strength and elongation at break with increasing TPEE loading, but a diminishing Young's modulus and tensile strength with respect to pure PLA. The blend at 30 wt% TPEE provided the optimum improvement in toughness, exhibiting an increase in the impact strength and elongation at break by 3.21- and 10.62-fold over those of the pure PLA, respectively. Scanning electron microscopy analysis illustrated a ductile fractured surface of the blends with the small dispersed TPEE domains in PLA matrix, indicating their immiscibility. The 70/30 (wt/wt) PLA/TPEE blend was subsequently filled with three loadings of BTN (1, 3, and 5 parts by weight per hundred of blend resin [phr]), where the impact strength, Young's modulus, tensile strength and thermal stability of all the blends were improved, while the elongation at break was deteriorated. Among the three nanocomposites, that with 1 phr BTN formed exfoliated structure and so exhibited the highest impact strength, elongation at break, and tensile strength compared to the other intercalated nanocomposites. Moreover, the addition of BTN was found to increase the thermal stability of the neat PLA/TPEE blend due to the barrier properties and high thermal stability of BTN.     

PP／EPDM复合材料性能研究

研究了聚丙烯（PP）／三元乙丙橡胶（EPDM）复合材料的结构、制备条件对复合材料力学性能的影响。结果表明：该复合材料拉伸强度、弯曲强度争弯曲模量主要是由连续相PP决定;EPDM在PP中的分布和形态影响材料的冲击性能;随着EPDM含量的增加材料的冲击强度提高到46．9kJ／m^2,断裂伸长率最大可达770％,但复合材料的流动性能略有下降。     

Effect of organoclay on the morphology, phase stability and mechanical properties of polypropylene/polystyrene blends

The effect of organically modified clay on the morphology, phase stability and mechanical properties of polypropylene (PP) and polystyrene (PS) blends was studied using three molecular weight grades of PP. Maleated polypropylene was used, at a PP-g-MA/organoclay ratio of 1, to preferentially promote dispersion of the organoclay in the PP matrix. The MMT content was fixed at 3 wt% based on the PP/PP-g-MA/MMT phase and the PS content was varied from 0-100 wt% in the blend. All blends were processed using a twin screw extruder. The organoclay resides in the PP phase and at the PP/PS interface. The dispersed PS particle size is significantly reduced by the presence of MMT, with maximum decrease observed for the low viscosity PP compared to its blend without MMT. The blends with MMT did not show any change in onset of co-continuity, though MMT shifts the phase inversion composition toward lower PS contents. The phase stability of the blend was significantly improved by the presence of MMT; for blends annealed at 210 °C for 2 h the dispersed phase particle size increased by as much as 10x without MMT with little change was noted with MMT present in the blend. The tensile modulus of blends improved with the addition of MMT at low PS contents. Blends based on the highest molecular weight grade PP showed increase in the tensile yield stress up to 40 wt% PS in the absence of MMT. The tensile strength at break for blend increased slightly with MMT while elongation at break and impact strength decreased in the presence of MMT. Surface energy analysis model was used to predict the orientation and equilibrium position of the clay platelet at the interface based on the surface energies.     

透明高抗冲聚苯乙烯树脂的工业化试验

在5kt／a高抗冲聚苯乙烯树脂装置上,以1,1-双(叔丁基过氧基)环己烷为引发剂、苯乙烯为单体、丁二烯-苯乙烯嵌段共聚物(简称K树脂)为增韧剂,采用自由基聚合工艺生产了透明高抗冲聚苯乙烯(HT-IPS)树脂,考察了HT-IPS树脂的微观结构、相对分子质量及其分布、流变性能、接枝反应程度、物理机械性能和光学性能,讨论了影响HT-IPS树脂结构及性能的因素。结果表明,HT-IPS树脂具有微观相分离结构,聚丁二烯链段为分散相、聚苯乙烯链段为连续相;HT-IPS树脂的流动性能略差于高抗冲聚苯乙烯树脂,且随着K树脂用量的增加,其流动性能变差,K树脂用量应控制在15份以下;在聚丁二烯链段的主链和侧链均发生了接枝反应,HT-IPS树脂具有较高的弯曲强度、弹性模量和拉伸强度,其光学性能、流变性能良好,但冲击强度较低,扯断伸长率较小。     

Processing and mechanical behavior of carbon black graded rubber compounds

Functionally graded rubber compounds (FGRCs) were prepared by construction based method. The matrix used was natural rubber (NR). Amorphous carbon black (N‐330) was used as grading material. The gradation of nanoparticles in a rectangular geometry comprised the variation of particle volume fraction along thickness direction. Its performance was evaluated for structural application through various mechanical and surface properties like tensile strength, modulus, tear strength, elongation at break, hardness, fracture surface by scanning electron microscopy, etc. At the same percentage of nanofiller loading, FGRCs show enhanced properties, i.e., modulus and tear strength (in some grades) compared to uniformly dispersed rubber compounds (UDRCs). Modulus of FGRCs, for a given particular stacking sequence of the layers, increases as much as by 275% compared to UDRCs. The ultimate properties like tensile strength and elongation at break made up for the modulus enhancement that decreases to as minimum as 50 and 80%, respectively. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010