硅橡胶/氟橡胶并用胶的制备及力学性能

硅橡胶和氟橡胶作为国防、航天等重要领域的耐热材料一直被人们青睐,但其有着各自地优缺点且价格昂贵,本文尝试将这两种橡胶制成并用胶以解决氟橡胶不耐低温和加工性差的问题,以期增大其使用温度范围。采用机械共混法制备硅橡胶/氟橡胶并用胶,研究了硅橡胶和氟橡胶的混炼工艺、并用比、共硫化体系和硫化条件对并用胶力学性能的影响。结果表明,当硅橡胶/氟橡胶的质量比为10∶90,共硫化体系为3~#硫化剂/过氧化二异丙苯(DCP),一段硫化温度为170℃、硫化压力为10MPa、硫化时间为30min,二段硫化温度为200℃、硫化时间为6h时,并用胶的力学性能达到最好。     

Simultaneous Enhancement of Mechanical and Dynamic Mechanical Properties of Natural Rubber/Recycled Ethylene-Propylene-Diene Rubber Blends by Electron Beam Irradiation

Mechanical and dynamic mechanical properties of natural rubber/recycled ethylene-propylene-diene rubber (NR/R-EPDM) blends were simultanoeusly enhanced by electron beam (EB) irradiation. The cross-linking promoter, trimethylolpropane triacrylate (TMPTA), was also introduced into the blends to induce the cross-linking. By applying EB irradiation, the tensile modulus, hardness, swelling, cross-link density, and storage modulus increased with increase in the irradiation dose; an irradiation dose of 50 kGy was efficient to gain optimum tensile strength. The formation of irradiation-induced cross-links after EB irradiation is a major concern for the enhancement of mechanical, swelling resistance, and dynamic mechanical properties of the blends.     

Properties of Low Density Polyethylene/Polypropylene Blends

ABSTRACT

The role of di-cumyl peroxide (DCP) as compatibilizer in low density Polyethylene/Polypropylene (LDPE/PP) blends has been explored. Mixtures with varying LDPE/PP ratio were prepared in a Brabender plasticorder and tested for their mechanical properties and calorimetric response. Then peroxide was added at concentrations up to 0.5%, and the mechanical properties of the these new blends were measured. Also, the mixing torque, melt flow index and gel content of the above products were recorded as a function of peroxide concentration. It was found that the incorporation of DCP restricts the thermoplastic characteristics of the melt, which was primarily attributed to branching which occurs in LDPE. This results in an enhancement in the adhesive bonding between the two polymers mainly due to chain entanglements. This was further supported by the fact that mechanical properties of the treated blend were significantly improved.     

LLDPE／LDPE共混体系的相容性与性能

ＬＬＤＰＥ／ＬＤＰＥ共混体系的相容性与性能杨毓华，花荣，白春霞，于旻李三喜，葛铁军（中国科学院长春应用化学研究所长春１３００２２）（沈阳化工学院高分子系沈阳）关键词ＤＳＣ，ＷＡＸＤ，力学性能，ＬＬＤＰＥ，ＬＤＰＥ，共混，相容性非晶－非晶－结晶共混体系...     

不同结构氧化锌对CIIR/ENR共混胶的气体阻隔性能和力学性能的影响

以重量比为90∶10的氯化丁基橡胶/环氧天然橡胶共混胶为基体,用密炼法将三种不同结构的氧化锌（普通条状氧化锌、片状氧化锌和纳米结构氧化锌）分散到基体中,研究不同结构的氧化锌对共混胶力学性能和气体阻隔性能的影响.结果表明片状氧化锌和纳米氧化锌复合胶比普通氧化锌复合胶强度下降,伸长率提高.片层氧化锌复合体系硫磺用量提高到2.0份,综合力学性能达到最好,且片状氧化锌能够赋予复合胶最佳的气体阻隔性能,比普通氧化锌体系提高了50％.     

PES／PC共混体系的相容性与力学性能

ＰＥＳ／ＰＣ共混体系的相容性与力学性能姜振华，马荣堂，寇喜春，安立佳（吉林大学化学系长春）（中国科学院长春应用化学研究所长春１３００２２）关键词聚醚砜，聚碳酸酯，共混物，力学性能聚醚砜（ＰＥＳ）是一种性能优异的特种工程塑料，它具有强度高、刚性大、耐热...     

相容剂对氯丁橡胶/天然橡胶并用胶性能的影响

本研究利用氯化丁基橡胶和腰果酚作为氯丁橡胶(CR)/天然橡胶(NR)并用胶的相容剂,将其按照一定比例在混炼过程中加入得到CR/NR混炼胶.CR/NR混炼胶在160℃下根据最佳硫化时间硫化得到并用胶.通过橡胶加工分析仪(RPA)研究发现腰果酚的加入,降低了CR/NR混炼胶的储能模量并且降低正硫化时间,提高了CR/NR混炼...     

聚乙烯-g-聚苯乙烯对线性低密度聚乙烯/聚苯乙烯共混物机械性能和发泡行为的影响

以通过开环易位聚合、加氢反应和原子转移自由基聚合技术结合制备的聚乙烯-g-聚苯乙烯(PE-g-PS)作为增容剂,研究了加入不同PS支链长度的PE-g-PS对于线性低密度聚乙烯/聚苯乙烯(LLDPE/PS)共混物的机械性能和发泡行为的影响。 以典型组成m(LLDPE):m(PS)=70:30共混物为例,考察了PE-g-PS对共混物拉伸性能的影响。 相对于二元共混物,增容剂的加入使得断裂伸长率、拉伸强度和屈服强度皆提高,且含长PS支链的增容体系提高更明显。 采用超临界CO₂釜式发泡工艺,考察了PE-g-PS中PS支链长度对共混物发泡行为的影响。 结果表明,相对于短PS支链体系,加入PE-g-PS_1.59k(PS相对分子质量为1590)后的泡孔结构更加均一,完全没有“缝隙”形貌的出现。 当发泡温度降至80 ℃时,即使存在LLDPE发泡空间限制作用(LLDPE无法发泡),加入支链长度更长的PE-g-PS_1.59k后泡孔分布也更加均一。     

Morphology and Mechanical Properties of Palm Based Fly Ash Reinforced Dynamically Vulcanized Natural Rubber/Polypropylene Blends

Palm based fly ash (PFA) is a solid waste of palm oil processing industry which contains silica components. These components are typically used to improve the mechanical properties of rubber-based products. This research aims to study the effect of the PFA as a filler on the morphology and properties of thermoplastic vulcanizate (TPV) based on a mixture of natural rubber (NR) and polypropylene (PP). TPV samples were prepared using the internal mixer at a mass ratio of NR/PP 70/30. Maleated polypropylene (MA-g-PP) 5% mass was added as a compatibilizer, filler content was varied from 15 to 45 per hundred rubber (phr). Paraffin and palm oil were added as a plasticizer with contents of 5 to 50 phr. Other additives include ZnO 5 phr, stearic acid 2 phr, trimethylquinone 1 phr, mercaptodibenzo-thiozyldisulfide 0.6 phr and 3 phr sulfur. The results showed that the use of PFA provides good tensile strength properties, a relatively homogeneous morphology, and low water absorption rate. The use of paraffin plasticizer produces a higher tensile strength compared to palm oil, but the elongation at break which produced the contrary. The best morphology and tensile properties of TPV (NR/PP 70/30) are on PFA and paraffin contents of 30 phr and 25 phr, respectively.     

Thermal Properties of Cis-1,4-Poly(butadiene)

Thermal properties of cis-1,4-poly(butadiene), Europrene cis, were investigated by means of thermal analysis and complementary methods. Thermal analysis of polymer was carried out both in air and inert atmosphere with a derivatgraph, DSC and internal TG-FTIR coupling system as well as internal TG, DTA-MS coupling system. It was found that investigations in air atmosphere the method of the sample preparation ofcis-1,4-poly(butadiene) influences the results of thermal analysis, which is connected with the rate oxygen diffusion into the reaction zone. Taking into consideration both the method of the sample preparing and atmosphere of thermal studies, the values of activation energy of destruction of cis-1,4-poly(butadiene) were determined. Using TG-FTIR and TG-MS methods, some products of thermal destruction of elastomer were determined.This revised version was published online in November 2005 with corrections to the Cover Date.     

Mechanical and Morphological Properties of Bio-Phenolic/Epoxy Polymer Blends

Polymer blends is a well-established and suitable method to produced new polymeric materials as compared to synthesis of a new polymer. The combination of two different types of polymers will produce a new and unique material, which has the attribute of both polymers. The aim of this work is to analyze mechanical and morphological properties of bio-phenolic/epoxy polymer blends to find the best formulation for future study. Bio-phenolic/epoxy polymer blends were fabricated using the hand lay-up method at different loading of bio-phenolic (5 wt%, 10 wt%, 15 wt%, 20 wt%, and 25 wt%) in the epoxy matrix whereas neat bio-phenolic and epoxy samples were also fabricated for comparison. Results indicated that mechanical properties were improved for bio-phenolic/epoxy polymer blends compared to neat epoxy and phenolic. In addition, there is no sign of phase separation in polymer blends. The highest tensile, flexural, and impact strength was shown by P-20(biophenolic-20 wt% and Epoxy-80 wt%) whereas P-25 (biophenolic-25 wt% and Epoxy-75 wt%) has the highest tensile and flexural modulus. Based on the finding, it is concluded that P-20 shows better overall mechanical properties among the polymer blends. Based on this finding, the bio-phenolic/epoxy blend with 20 wt% will be used for further study on flax-reinforced bio-phenolic/epoxy polymer blends.     

Barrier,Mechanical, Morphological and Thermal Properties of Compatibilized High Density Polyethylene and Polyamide 6 Blends

Effectiveness of the content of maleic anhydride (MAH) and polyamide 6 (PA6) on mechanical, thermal, barrier (moisture and oxygen) properties of HDPE/PA6 blends was investigated. Blends of HDPE with PA6 were prepared by in situ method. Molau test and FTIR spectroscopy results confirmed the reactive compatibilization through grafting of MAH on HDPE and PA6 chains in PA6/HDPE blends. Low concentration of benzoyl peroxide (BPO) and MAH reduced the particle size, improved phase morphology and mechanical properties of PA6/HDPE blends. Decrease in mechanical properties of PA6/HDPE blends was observed at high concentration of BPO and MAH.     

线性低密度聚乙烯／乙烯醋酸乙烯共聚物共混体系的相容性及性能

线性低密度聚乙烯／乙烯醋酸乙烯共聚物共混体系的相容性及性能杨毓华＊白春霞花荣于李三喜（中国科学院长春应用化学研究所长春１３００２２）（沈阳化工学院高分子科学与工程系沈阳）关键词线性低密度聚乙烯，乙烯醋酸乙烯共聚物，共混，相容性，ＤＳＣ，ＷＡＸＤ，力...     

PS／LDPE共混体系相结构的TEM研究

ＰＳ／ＬＤＰＥ共混体系相结构的ＴＥＭ研究徐世爱，江明，沈静姝（复旦大学高分子科学系和聚合物分子工程实验室，上海，２００４３３）（中国科学院化学研究所高分子物理开放实验室）关键词相结构，透射电镜，共混体系聚苯乙烯（ＰＳ）和低密度聚乙烯（ＬＤＰＥ）共混体...     

Reactive Compatibilization of Polyethylene/Ground Tire Rubber Inhomogeneous Blends via Interactions of Pre-Functionalized Polymers in Interface

Summary: Reactive compatibilization of recycled low- or high-density polyethylenes (LDPE and HDPE, respectively) and ground tire rubber (GTR) via chemical interactions of pre-functionalized components in their blend interface has been carried out. Polyethylene component was functionalized with maleic anhydride (MAH) as well as the rubber component was modified via functionalization with MAH or acrylamide (AAm) using chemically or irradiation (γ-rays) induced grafting techniques. The grafting degree and molecular mass distribution of the functionalized polymers have been measured via FTIR and Size Exclusion Chromatography (SEC) analyses, respectively. Thermoplastic elastomer (TPE) materials based on synthesized reactive polyethylenes and GTR as well as ethylene-propylene-diene rubber, EPDM were prepared by dynamic vulcanization of the rubber phase inside thermoplastic (polyethylene) matrix and their phase structure, and main properties have been studied using DSC and mechanical testing. As a final result, the high performance TPE with improved mechanical properties have been developed.     

固相法氯化聚乙烯对PVC／LLDPE共混体系性能和形态的影响

采用固相法氯化聚乙烯（ＣＰＥ）对聚氯乙烯／线型低密度聚乙烯（ＰＶＣ／ＬＬＤＰＥ）共混体系进行增容改性。扫描电子显微镜、透射电子显微镜、动态力学分析和力学性能测试结果表明，ＣＰＥ对ＰＶＣ／ＬＬＤＰＥ共混体系具有很好的增容作用。     

Effect of Electron Beam Irradiation on the Properties of High Styrene Rubber/Styrene Butadiene Rubber Blends

High styrene rubber (HSR)/styrene butadiene rubber (SBR) blends at different ratios were exposed to various doses of electron beam irradiation. The effect of irradiation dose and blend ratios on the mechanical properties and shape memory characteristics in terms of strain fixation) rate (R_f) and strain recovery rate (R_r) was investigated. The results revealed that rich styrene blends displayed higher tensile strength and hardness than low styrene content blends at all irradiation doses. However, elongation at break, and toughness were lower for rich styrene content. Also, it was observed that for most specimens, the tensile strength, elongation at break and hardness increases up to100 kGy. Increasing irradiation doses resulted in slight deterioration in some mechanical properties only for low styrene content at150 kGy. According to the normalized tensile stress at 25% elongation, it was found that the contribution of irradiation in enhancing the mechanical properties is higher for rich butadiene blends. On the other hand, it was observed that rich styrene content blends possess higher R_f and R_r at all the irradiation doses and stretching temperatures. However, the increase of irradiation dose decreases R_f values; the extent of this decrease depends on the blend ratios. Conversely, for all blends, R_r were increased by increasing irradiation dose and styrene content ratios.     

橡胶木粉填充LLDPE复合材料的结构和力学性能

用橡胶木粉填充线性低密度聚乙烯(LLDPE),研究了酸、碱溶液预处理木粉的效果和硅烷偶联荆(KH-570)、MMA接枝的天然橡胶胶乳(MGL-30)两种改性剂对橡胶木粉表面改性的效果,以及未粉粒径和填充量等对木粉／LLDPE复合材料力学性能的影响,并用SEM对复合材料拉伸断面的形态结构进行了分析。结果表明：木粉的拉径、木粉填充量和改性荆用量对复合材料的力学性能有较大的影响,经碱溶液预处理再用改性荆改性后的木粉能有效地改善木粉与LLDPE的界面粘结强度,提高橡胶木粉／LLDPE复合材料的力学性能。     

Rheology and Physical Properties of Polyethylene/Polyethylene‐Ionomer Blends and their Clay Nanocomposites

Rheological and solid‐state physical properties of blends containing high‐density polyethylene (HDPE) and a polyampholyte derivative (PE‐g‐PA) are assessed along with their onium ion‐exchanged montmorillonite clay (NR‐MM) nanocomposites. Strong deviations from the log‐additivity rule of zero‐shear viscosity, combined with synergistic behavior in tensile moduli, are consistent with a multi‐phase blend morphology. While this affects clay dispersion in filled blends, PE‐g‐PA/HDPE based nanocomposites are shown to exhibit a favorable balance between material stiffness and ductility.