共查询到18条相似文献,搜索用时 171 毫秒
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本工作主要利用DSC、x-射线衍射、小角激光光散射以及偏光显微镜等方法,对天然橡胶/低密度聚乙烯共混体系(NR/LDPE)中LDPE的晶体结构、结晶度、球晶尺寸和形态、微晶尺寸、成核过程以及结晶动力学等方面进行了研究,得到了一些有意义的结果。 相似文献
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顺丁橡胶/低密度聚乙烯的共混 总被引:1,自引:0,他引:1
比较了未交联和动态交联不同组成PB/LDPE共混物的力学性能。共混物的T_g、T_m和T_d不随组成而变化,表明PB和LDPE不具有相容性。但共混物中PE的γ转变向高温方向位移,说明PE非晶部分的分子短链和PB有界面相互作用。形态研究表明,未交联体系中量多的组份形成连续相,动态交联体系在PB/LDPE≤70/30时,PE呈连续相,交联的PB为分散相。 相似文献
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LDPE/EVA共混体系的结晶行为 总被引:2,自引:0,他引:2
本文通过DSC、WAXD、偏光显微镜、DMA等方法,对LDPE/EVA共混体系进行了研究。结果表明,EVA可使LDPE的熔融峰温提高15℃。并在LDPE结晶过程中起稀释剂作用。LDPE/EVA共混体系为非晶相相容。 相似文献
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高密度聚乙烯/天然橡胶共混体系的流变性能研究方征平,许承威(杭州大学化学系杭州310028)关键词高密度聚乙烯,天然橡胶,共混物,流变,改性用橡胶与聚乙烯共混是提高后者的物理机械性能,尤其是耐环境应力开裂性能(ESCR)的主要方法之一“-“.然而,由... 相似文献
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HDPE/LDPE共混体系的晶性研究 总被引:1,自引:0,他引:1
用DSC和WAXD方法考察了高密度聚乙烯和低密度聚乙烯共混体系(HDPE/LDPE)的结晶性能。结果表明,在共混物中HDPE含量大于50%时,共混物只出现HDPE的熔融峰,且熔融温度随HDPE含量减小而降低;LDPE含量大于50%时,DSC图上只出现熔点介于HDPE和LDPE之间的新熔融峰。DSC和WAXD法所测结晶度均偏离共混物的线性加和值,而晶胞参数则随共混物组成变化出现最小值,表明HDPE和LDPE可以形成共晶相容体系。Raman光谱测得介晶相αb值的膨胀,支持这一观点。 相似文献
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研究了马来酸酐接枝的聚乙烯辛烯弹性体 /半结晶性塑料共混物 (TPEg)对热塑性共聚聚酯(PETG) /聚乙烯辛烯弹性体 (TPE)共混体系增容增韧作用的影响 .马来酸酐接枝物显著地改善了PETG与TPE之间的相容性 ,导致TPE分散相颗粒细化 ,并促使分散相颗粒面间距等于甚至小于实现脆韧转变所需的临界面间距 .在固定PETG基体含量为 85wt %的前提下 ,当TPEg在 15 %分散相中的含量由 2 0 %增加到30 %时 ,即TPEg在共混体系中的含量由 3 %增加到 4 5 %时 ,共混体系出现了由脆性到韧性的转变 ,冲击强度急剧升高 相似文献
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壳核结构增韧剂对热塑性共聚酯/聚乙烯辛烯弹性体共混体系增容与增 … 总被引:3,自引:0,他引:3
研究了马来酸酐接枝的聚乙烯辛烯弹性体/半结晶性塑料共混物(TPEg)对热塑性共聚聚酯(PETG)/聚乙烯辛烯弹性体(TPE)共混体系增容增韧作用的影响。马来酸酐接枝物显著地改善了PETG与TPE之间的相容性,导致TPE分散相颗粒细化,并促使分散相颗粒面间距等于甚至小于实现脆韧转变所需的临界面间距。在固定PETG基体含量为85wt%的前提下,当TPEg在15%分散相中的含量由20%增加到30%时,即 相似文献
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Bharat P. Kapgate Chayan Das Amit Das Debdipta Basu Uta Reuter Gert Heinrich 《Journal of Sol-Gel Science and Technology》2012,63(3):501-509
Silica particles were generated and grown in situ by sol–gel method into rubber blends comprised of natural rubber (NR) and acrylonitrile butadiene rubber (NBR) at various blend ratios. Silica formed into rubber matrix was amorphous in nature. Amount of in situ silica increased with increase in natural rubber proportion in the blends during the sol–gel process. Morphology studies showed that the generated in situ silica were nanoparticles of different shapes and sizes mostly grown into the NR phase of the blends. In situ silica filled NR/NBR blend composites showed improvement in the mechanical and dynamic mechanical behaviors in comparison to those of the unfilled and externally filled NR/NBR blend composites. For the NR/NBR blend at 40/60 composition, in particular, the improvement was appreciable where size and dispersion of the silica particles into the rubber matrix were found to be more uniform. Dynamic mechanical analysis revealed a strong rubber–in situ silica interaction as indicated by a positive shift of the glass transition temperature of both the rubber phases in the blends. 相似文献
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Nabil Hayeemasae Indra Surya Hanafi Ismail 《International Journal of Polymer Analysis and Characterization》2016,21(5):396-407
Biocompatibilizer-based refined, bleached, deodorized palm stearin was successfully used as compatibilizer for natural rubber/recycled ethylene–propylene–diene rubber (NR/R-EPDM) blends. It seems effective in improving the state of cure, tensile properties, as well as the swelling resistance and morphology of the blends, indicating an improvement in compatibility between the NR matrix and R-EPDM rendered by biocompatibilizer. This was clearly verified by the dynamic mechanical properties of the blends. The dynamic responses obtained were clearly corresponding to the swelling result. It proves that the cross-link density plays a major role in the changes of storage modulus and degree of entanglement. 相似文献
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The present work aims to prepare thermal and oxidation resistant Natural Rubber (NR) composites using antioxidant-modified nanosilica (MNS). The thermo-oxidative aging performance of the composites was evaluated by the variations in mechanical properties after aging at 100 °C for 24 h. The performance was further monitored through Scanning Electron Microscopy, Fourier Transform Infrared spectroscopy, Thermogravimetric Analysis, and Dynamic Mechanical Analysis. NR nanocomposite with 1–7.5 phr nanosilica (NS) and 3 phr MNS were prepared and its rheological properties were studied. A comparative study of the theoretical models yielded that modified Guth-Gold equation predicted Young's modulus better than other models. Thermal stability of natural rubber MNS composite was improved by 10 °C with pre-eminent mechanical properties like tensile strength and heat build-up. A linear relationship of compression set with modulus of all composites were also established. Equilibrium swelling test revealed improved crosslink density in NR MNS composite. The strong interaction between antioxidant and nanosilica enabled low migration of antioxidant in NR MNS composite. Hence its protective function after aging showed more effective than NR NS composites. These versatile functional properties of NR MNS composite suggest its potential application in electrical, electronic and high performance rubber products. 相似文献
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Isoprene units in natural rubber (NR) and its synthetic analogues were quantified by 1H-NMR spectroscopy using polyethylene glycol (PEG) as an internal standard. The effect of PEG and rubber concentrations, molar ratio of rubber/PEG, measuring temperature and scan number on the quantification was investigated to establish the respective working range. Analysis of commercial grades of NR revealed that the differences in 1,4 isoprene content is caused by the production process and feedstock, in which proteins and lipids were found to be the major impurity in NR. Gel fraction of NR has insignificant effect on the measurement of 1,4 isoprene content. Furthermore, the new method was found to produce good results for the quantification of 1,4 and 3,4 units of synthetic polyisoprenes. 相似文献
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<正> 含10%摩尔以下的离子且主链为柔性的离聚体是一种热塑性弹性体。在动态力学性质方面呈现特殊的行为,表现在贮能模量(1gE′)与温度的关系中有橡胶态平台出现。最早Otocka等指出,(丁二烯-甲基丙烯酸)共聚物无橡胶态平台,经金属离子中和后产生橡胶态平台,且E′增加。Agarwal,Makowski等则报道磺化乙丙胶离聚体的橡胶态平台随离子含量提高而加宽,随硬脂酸锌的加入而缩短。Fitzgerald及Weisst结合X-射线小角散射研究了甘油及邻苯二甲酸二辛酯对磺化聚苯乙烯离聚体的动态力学性质的影响。 相似文献
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The scanning electron microscopy method in combination with the selective etching technique for polymer blends have been used to evaluate interfacial interaction in natural rubber and low density polyethylene blends. The morphology of the polymer blends, studied under externally applied strain, has been investigated to understand the role of interface adhesion between natural rubber and polyethylene phases, for two separate crosslinking systems, i.e. sulphur and peroxide.
Externally induced strain which facilitates phase separation in sulphur cured blends by initiating cracks at the interface; peroxide curing prevents separating out of the polyethylene phase from the natural rubber matrix. In the latter case, induced stress is distributed predominantly by developing fine flaw paths in the rubber matrix.
The method which has been developed for natural rubber and polyethylene blend systems may be used to evaluate the degree of interfacial adhesion between the dispersed phase and the dispersion medium for other kinds of polymer-polymer, polymer-filler as well as polymer-fibre composites. 相似文献