尼龙11/蒙脱土纳米复合材料的研究

采用熔体插层法制备了尼龙11／蒙脱土纳米复合材料。研究了纳米蒙脱土对尼龙11力学性能的影响。结果表明,在蒙脱土含量为5％时,尼龙11／蒙脱土纳米复合材料的冲击强度达到最大值,是纯尼龙11冲击强度的2．5倍;随着蒙脱土含量的增加,复合材料的拉伸强度先降低后升高,但变化幅度不大。通过电镜观察冲击断面形态发现,蒙脱土以片状形式均匀分散在尼龙11基体中,受冲击时基体产生了屈服。     

HIPS回料改性树脂的研究和应用

研究了HIPS回料的性能,研制了一种HIPS回料改性树脂,在HIPS回料中添加改性剂使HIPS回料改性树脂的性能得到极大的提高。试验结果表明:HIPS回料改性树脂的性能可以达到或超过HIPS新料的性能。在HIPS回料中添加SBS树脂,可以明显提高冲击强度和断裂伸长率,而拉伸强度和洛氏硬度有所下降;添加K树脂可以提高改性树脂的熔体流动速率;添加纳米蒙脱土可以提高改性树脂的拉伸强度、断裂伸长率、冲击强度、弯曲强度、弯曲模量、热变形温度、维卡软化点和洛氏硬度以及熔体流动速率。采用SBS树脂和K树脂以及纳米蒙脱土等材料组成的配方体系,可以制得符合使用要求的HIPS回料改性树脂,经生产应用表明,HIPS回料改性树脂的性能能够满足实际使用要求。     

中空容器专用HDPE(HD5502GA)/nano-MMT复合材料力学性能分析

以HDPE(HD5502GA)和纳米蒙脱土为实验原料,分别配制纳米蒙脱土和改性纳米蒙脱土质量分数为1%、3%、5%、7%、9%的HDPE/nano-MMT混合料,再经双螺杆挤出机造粒后得到HDPE/nano-MMT复合材料。分别以纯HDPE和不同组分的HDPE/nano-MMT以及HDPE与改性纳米蒙脱复合材料为实验材料,经小型平板硫化机压片后,用仿形制样机和全自动缺口仪制备出抗缺口冲击样条,用仿形制样机制备出1A型试样样条,并对样条进行力学性能测试。实验结果表明,随着纳米蒙脱土含量的增加,复合材料的拉伸强度和抗缺口冲击强度都呈现出逐渐减小的趋势。随着改性纳米蒙脱土含量的增加,样条的拉伸强度呈现出先减小后增大再减小的趋势,当改性蒙脱土含量为1%时,复合材料的拉伸强度最大,为29.864 MPa;随着改性纳米蒙脱土含量的增加,样条的抗缺口冲击强度呈现出先增大后减小的趋势,当改性纳米蒙脱土的含量为3%时,复合材料的冲击强度最大,为11.932 kJ/m~2。     

纳米蒙脱土／环氧树脂复合材料的插层剥离及性能研究

考察了纳米蒙脱土在环氧树脂中的插层剥离行为，发现提高环氧树脂在蒙脱土层间的固化反应速率，有利于促进层间反应在与层外反应的竞争中胜出，有利于蒙脱土在环氧树脂中的剥离。制备了纳米蒙脱土/环氧树脂复合材料，性能测试显示复合材料的力学性能和热性能均比纯环氧树脂有所提高，无缺口冲击强度提高了177．8％，拉伸强度提高了46．5％，热变形温度提高了13．2℃。     

尼龙11/蒙脱土纳米复合材料形态和性能研究

通过熔融共混法成功地制备了不同含量蒙脱土的尼龙11/蒙脱土纳米复合材料,利用X衍射(XRD)和透射电镜(TEM)研究了尼龙11/蒙脱土纳米复合材料的微观结构。结果表明,当蒙脱土质量分数小于2%时,形成了剥离型的纳米复合材料,当蒙脱土质量分数超过2%时形成了插层型的纳米复合材料。热重分析表明当蒙脱土质量分数为2%时,纳米复合材料的热分解温度比纯尼龙11提高了27℃。不同蒙脱土含量的纳米复合材料悬臂梁冲击强度均比纯尼龙11的高,但其拉伸强度在蒙脱土质量分数小于8%时降低,以后随蒙脱土含量的增加而提高。     

尼龙1212/蒙脱土纳米复合材料的制备与性能研究

通过插层聚合制备了尼龙1212／蒙脱土纳米复合材料，研究了反应条件、蒙脱土含量对复合材料性能的影响，并分析了原因。结果表明，聚合时加搅拌所制备复合材料的性能优于未加搅拌的，反应温度为240℃时复合材料的拉伸强度最高；蒙脱土含量为4％时，复合材料的拉伸强度达到最大值，比纯尼龙1212提高18．9％，蒙脱土含量为6％时，复合材料的缺口冲击强度最高，比纯尼龙1212提高21．3％。     

ABS/蒙脱土纳米复合材料的制备、结构及性能

将SAN／蒙脱土纳米复合材料与ABS高胶粉熔融共混得到ABS／蒙脱土纳米复合材料。对纳米复合材料的机械性能进行了表征．结果发现蒙脱土的加入一定程度上提高了ABS的杨氏模量和弯曲模量，但冲击强度有明显的降低。采用XRD、TEM和SEM对纳米复合材料的结构进行表征，结果表明在共混过程中，蒙脱土片层的物理特性导致其基本分布在橡胶粒子的表面．甚至造成粒子的变形和破裂；ABS／蒙脱土纳米复合材料在冲击过程中，蒙脱土片层的分散状态导致橡胶粒子不能发生塑性变形，冲击断面呈多孔形态。     

有机阳离子插层蒙脱土改性骨胶的制备与性能研究

使用有机阳离子溴化铵盐对蒙脱土进行了有机化处理,利用插层法制备了改性骨胶／蒙脱土杂化材料。并对不同蒙脱土含量的复合材料的拉伸剪切强度、初黏力与纯改性骨胶进行比较。试验结果表明,经有机阳离子溴化铵盐处理的蒙脱土与改性骨胶具有良好的相容性。纳米蒙脱土通过插层处理使之变为有机纳米蒙脱土后,能显著改善改性骨胶的综合性能,粘接试样的拉伸剪切强度、初黏力都得到了显著提高。     

多功能高性能环氧树脂复合材料的制备

通过将有机蒙脱土和纳米TiO_2共同添加到环氧树脂中,制备出一种在多项性能上都有大幅提高的高性能多功能有机蒙脱土/纳米TiO_2/环氧树脂复合材料。通过XRD和TEM分析可知,由于利用了有机蒙脱土、纳米TiO_2与环氧树脂间的相互作用,蒙脱土层被高度剥离,所得的二维蒙脱土纳米单片与零维纳米TiO_2颗粒交错分布于树脂基体中。测试表明:有机蒙脱土/纳米TiO_2/环氧树脂复合材料在多项性能上都比纯环氧树脂和有机蒙脱土/环氧树脂复合材料高,拉伸模量分别提高了254.75%和135.69%,拉伸强度分别提高了181.53%和243.46%,弯曲模量分别提高了121.12%和106.04%,弯曲强度分别提高了125.25%和116.98%,缺口冲击强度分别提高了165.57%和137.23%;同时材料的耐沾污性也达到了0级的无污染水平。     

高冲击强度聚苯乙烯的协效阻燃研究

采用熔融共混法制备了高冲击强度聚苯乙烯(HIPS)/高性能纳米氢氧化铝(CG-ATH)/有机改性蒙脱土(OMMT)/包覆红磷(ERP)纳米复合材料,研究了OMMT和ERP用量对复合材料阻燃性能和力学性能的影响。结果表明:纳米CG-ATH、OMMT和ERP之间有很好的协效阻燃效果,当纳米CG-ATH用量为15%,OMMT用量为3%,ERP用量为10%时,HIPS复合材料的垂直燃烧可达到UL94V—0级,此时,复合材料具有较好的弯曲性能和拉伸性能,但冲击性能较差。     

Super HIPS: improved high impact polystyrene with two sources of rubber particles

Significant improvements in impact strength were achieved in polystyrene blends that combined conventional HIPS particles in combination with particles produced by compositional quenching. A commercial HIPS was solvated and blended with additional polystyrene, rubber and diblock copolymer, and the mixture was flash devolatilized to give the end-product. Impact strengths of injection and compression molded samples and tensile properties are reported. It is known that the best impact modified polystyrene obtained by compositional quenching, here called aHIPS, has smaller and lower modulus rubber particles than conventional HIPS, and has more than twice the impact strength of conventional HIPS. The novel blends of HIPS and aHIPS reported here exhibit synergism, the impact strength of the blend being higher than expected as a linear average of the component properties. The rubber phase volume including occlusion was held at 23%. An interior optimum in rubber efficiency (i.e. Izod impact per unit weight of rubber) was observed when 75% of the phase volume was derived from HIPS while an interior minimum was observed when 25% of the phase volume was derived from HIPS. The elongation at break and tensile impact strength exhibited a form of negative synergism, indicating that conventional HIPS is superior in low speed tests and aHIPS is better in high speed tests such as Izod.     

Synthesis and mechanical properties of high impact polystyrene with in situ bulk polymerization toughened by one‐pot Nd‐based styrene–isoprene–butadiene terpolymer rubber

High impact polystyrene (HIPS) resins were obtained with in situ bulk polymerization toughened by styrene–isoprene–butadiene terpolymer rubber (SIBR). SIBR prepolymer was prepared through selective polymerization of styrene (St), isoprene (Ip), and butadiene (Bd) in St with [Nd]/[Al]/[Cl] catalyst. Nd‐based catalyst exhibited more favorable activity toward conjugated diene other than St, resulting in St solution of random SIBR with high cis‐1,4 stereoregularity and low St content, which was directly exposed to the free radical polymerization of St to generate HIPS. Effect of toughened rubber and the initiators [difunctional (D2) and trifunctional (T3)] were examined to attain HIPS possessing mechanical properties as follow: impact strength, 0.9–24.8 kJ/m²; tensile strength, 16.0–27.5 MPa; and elongation at break, 7.4–107.0%. Increasing SIBR matrix in HIPS improved the impact strength and decreased tensile strength. The fracture surface morphologies of HIPS specimens were studied by notched impact tests and scanning electron microscopy (SEM), illustrating that the incremental SIBR matrix presented synergistic toughening effect of crazing to enhance the ductile fracture behavior. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43979.     

Comparison of polystyrene,poly(styrene/acrylonitrile), high-impact polystryrene,and poly(acrylonitrile/butadiene/styrene) with respect to tensile and impact properties

The tensile behaviors of polystyrene (PS), poly(styrene/acrylonitrile) (SAN), high-impact polystyrene (HIPS), and poly(acrylonitrile/butadiene/styrene) (ABS) were examined systematically in the wide range of strain rate, 1.7 × 10^?4–13.1 m/s. When glassy and brittle PS was a criterion, the incorporation of a polar group (SAN) only strengthened the hardness, and the fracture mode was the same as for PS. The introduction of dispersed rubber particles (HIPS) weakened the hardness a little but offered a new deformation mechanism, i.e., microcrazing (whitening), and contributed to the improvement of impact strength. In the heterogeneous system, the enhancement of matrix strength [e.g., preorientation or blending with poly(phenylene oxide) for HIPS] makes possible another deformation mechanism, i.e., shear band formation (cold drawing), which is superior to microcrazing for achieving higher impact strength. ABS, which incorporates concurrently two factors (polar group to matrix phase and dispersed rubber particles), can be regarded as an enhancement of the matrix strength of HIPS. In spite of the remarkable magnitude of its impact strength compared with that of the other three polymers, the deformation mechanism of ABS was limited to microcrazing. This indicated that only the introduction of a polar group (as nitrile group) could not strengthen the matrix as much as preorientation or blending with poly(phenylene oxide).     

BR/EVA/HIPS TPV的制备和性能研究

采用苯乙烯-丁二烯-苯乙烯嵌段共聚物(SBS)改善BR/乙烯-乙酸乙烯酯共聚物(EVA)/高抗冲聚苯乙烯(HIPS)共混物的界面相容性,通过动态硫化法制备BR/EVA/HIPS TPV,并对其性能进行研究.结果表明:未加入SBS的BR/EVA/HIPS共混物未表现出橡胶类弹性体特征,而加入适量SBS的共混物表现出典型橡胶类弹性体特征;当SBS用量为8～12份时,BR/EVA/HIPS TPV的综合物理性能较好,拉伸断面平滑,界面相容性良好.     

Rheological,mechanical and morphological properties of thermoplastic vulcanizates based on high impact polystyrene and styrene‐butadiene rubber

Thermoplastic vulcanizates (TPVs) based on high impact polystyrene (HIPS)/styrene‐butadiene rubber (SBR) blends were prepared by dynamic vulcanization technique. The rheological, mechanical and morphological properties of the dynamically vulcanized blends were investigated systematically. As determined by capillary rheometer, the apparent viscosity of the blends decreases as the shear rate increases, indicating obvious pseudoplastic behavior. At low shear rate, the apparent viscosity of these blends is considerably higher than that of neat HIPS and decreases with the increase of HIPS concentration. The increase of HIPS content in the dynamically vulcanized blends contributes to the increase of tensile strength and hardness properties, while elongation at break and tensile set at break reach a maximum at 30 and 50 wt % of the HIPS content, respectively. The etched surfaces of the HIPS/SBR TPVs were investigated using field‐emission scanning electron microscopy, the morphological study reveals continuous HIPS phase and finely dispersed SBR elastomeric phase in the TPVs. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

氨基模塑料耐电击穿和耐冲击性能研究

简要介绍了氨基模塑料的基本生产工艺流程,探索了玻璃纤维、纳米蒙脱土、丁腈橡胶粉、玉米淀粉等对氨基模塑料耐电击穿性能和缺口冲击强度的影响。实验结果表明,玻璃纤维作为增强剂对氨基模塑料的电气强度提高效果最为明显,而缺口冲击强度呈下降趋势;纳米蒙脱土的加入使氨基模塑料性能都有提高;玉米淀粉的加入对氨基模塑料的电气强度影响不明显,对缺口冲击强度略有提高;而丁腈橡胶的加入使氨基模塑料的电气强度明显下降,缺口冲击强度提高比较明显,但随丁腈橡胶加入量的增加影响不显著。改性后的氨基模塑料的电气强度能超过17 kV/mm,缺口冲击强度最高可以达到2.7 kJ/m2,最佳耐电压时间在100 s以上。     

酚醛树脂改性纳米蒙脱土填充PA6的制备及性能研究

分别利用经十八烷基三甲基氯化铵(OTAC)、酚醛树脂(PF)表面改性的纳米蒙脱土(MMT)填充聚酰胺(PA)6,研究了不同表面改性剂及其用量对PA6的力学性能、热性能和吸水性的影响。结果表明,经OTAC改性的纳米MMT和经PF改性的纳米MMT对PA6的热性能改善效果有限,但有利于提高PA6的刚性和降低吸水性。PF改性纳米MMT对PA6的改性效果优于OTAC改性纳米MMT,当PF改性纳米MMT的质量分数为3%时,材料的拉伸强度、弯曲强度和维卡软化温度分别比纯PA6提高了12.3%、58.8%和2%,吸水率降低0.5%。     

Degradation of high‐impact polystyrene with processing and its recovery via the addition of styrene–butadiene rubber and styrene–ethylene–butylene–styrene block copolymer

This work was divided into three parts. First, high‐impact polystyrene (HIPS) was submitted to a series of extrusion cycles with the objective of evaluating the consequent variations in its thermal and mechanical properties. The results showed slight variations in both the thermal and mechanical properties of HIPS. Second, degraded HIPS/styrene–ethylene–butylene–styrene (SEBS) blends and degraded HIPS/styrene–butadiene rubber (SBR) blends were prepared to evaluate the influence of the elastomeric concentration on the polymer's properties. The incorporation of SEBS or SBR allowed the recovery of the initial properties shown by virgin HIPS. Finally, blends of degraded HIPS with 2 wt % SEBS or SBR were extruded through four cycles. The mechanical properties remained constant with 2% SEBS added, whereas the mixtures of HIPS with 2% SBR showed an increase in the tensile strength as the number of extrusion cycles increased. The Vicat softening temperature decreased in both cases. The use of differential scanning calorimetry permitted the observation of differences in the crosslinking reactions of different samples as a function of the number of extrusion cycles. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Toughening study of fire‐retardant high‐impact polystyrene

Fire‐retardant high‐impact polystyrene (HIPS) was modified by melt blending with varying amounts of three types of tougheners. The effects of the tougheners on the properties of the fire‐retardant HIPS were studied by mechanical, combustion tests, and thermogravimetric analysis. The morphologies of fracture surfaces and char layers were characterized through scanning electron microscopy. The results show that the impact properties of styrene–butadiene–styrene (SBS)‐containing composites were better than those of ethylene–propylene–diene monomer (EPDM)‐containing or ethylene–vinyl acetate copolymer (EVA)‐containing composites. The tensile strength and flexural modulus of the fire‐retardant HIPS decreased evidently with the addition of tougheners. It is found that the compatibility between SBS copolymer and HIPS matrix was best among the three types of tougheners. The addition of SBS had little influence on the thermal property, residue, flammability, and morphology of char layer of the fire‐retardant HIPS, but the addition of EPDM rubber or EVA brought adverse influence on the residue, flammability, and morphology of char layer of the fire‐retardant HIPS, especially for EPDM. Copyright © 2009 John Wiley & Sons, Ltd.