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In order to improve the toughness, wear resistance, and combustion properties of the monomer casting nylon (MC nylon) materials, the polydimethylsiloxane (PDMS) segment is bonded to the nylon molecular chain by copolymerization. PDMS/MC nylon copolymers are prepared via in situ anionic polymerization with macro-activator based on PDMS terminated with hexamethylene diisocyanate. The effects of different macro-activator content on the mechanical properties, water absorption, thermal stability, friction and wear properties, and combustion properties of the copolymers are characterized. The results show that the impact strength of the copolymer improves significantly (optimally increases by 2.6 times) and the water absorption rate decreases with the increase of PDMS content. The introduction of the silicon–oxygen structure reduces the peak heat release rate of copolymer materials (optimally decreases about 28.7%), while it promotes the decomposition of the system, resulting in a slight decrease in the thermal stability of the materials. Adding 5 wt % PDMS can decrease the wear loss of MC nylon from 6.2 mg of pure nylon to 1.6 mg. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48753. 相似文献
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A series of monomer casting (MC) nylon‐6/SiO2 composites were prepared via in situ polymerization. It was found that the tensile strength, storage modulus, and notched charpy impact strength of the composites were improved and reached maximum at 3–5 wt% loading of SiO2. The α relaxation peak corresponding to the glass transition temperature (Tg) shifted to high temperature with increasing SiO2 content. Addition of SiO2 led to an increase of the melting and crystallization temperatures, and crystallinity. It also reduced the induction time of crystallization, advance the crystallization process of MC nylon‐6, and improve the crystal growth rate. The self‐nucleation crystallization analysis indicated that SiO2 particles played the role of facilitating the crystallization of the matrix mainly via accelerating the generation of crystal nucleus. By addition of SiO2 particles, the fracture surface of MC nylon‐6 changed to distant striations with many yield folds accompanied by a large number of stress whitening, displaying much obvious character of tough fracture. SiO2 particles can be pulled‐out under stress by being covered with MC nylon‐6 resin due to strong interfacial interaction and presented a skin–core structure. © 2012 Society of Plastics Engineers. 相似文献
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采用差示扫描量热法(DSC)研究了阴离子原位聚合法制备的铸型尼龙6(MC尼龙6)/TiO2纳米复合材料的等温结晶行为,并应用Avrami方程分析了MC尼龙6的等温结晶动力学过程.结果表明纳米TiO2对MC尼龙6基体具有异相成核作用,使其原位纳米复合材料结晶速率常数变大,半结晶时间变小.Hoffman成核结晶理论计算结果表明,原位纳米复合材料的Kg(与结晶温度无关而与成核方式有关的参数)大于MC尼龙6且随着纳米含量的增加而增加,说明纳米TiO2阻碍了MC尼龙6分子链的运动,同时尼龙6由晶核生长占主导地位逐渐向成核机制占主导地位转变. 相似文献
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铸型尼龙是以己内酰胺为单体,强碱性物质为催化剂,与助催化剂等助剂一起,经过真空脱水后直接注入到已预热至一定温度的模具中,聚合成固体坯料。根据阴离子聚合反应的机理,考察了催化剂、助催化剂、改性剂等因素对材料拉伸强度、断裂伸长率、硬度和冲击强度等指标的影响,分析了各指标的变化规律及联系。实验结果表明,真空度为1.333kPa,氢氧化钠一般是己内酰胺的0.4%~0.5%·mol-1,列克纳胶用量为4mL,材料的综合性能较佳。 相似文献
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Li-Yun Zheng Kin-Tak Lau Li-Xin Zhao Yong-Qiang Zhang David Hui 《Chemical Engineering Communications》2013,200(3):343-351
Nano-Al2O3-reinforced monomer casting nylon (NA/MCN) composites were prepared by using in situ polymerization. The average molecular weight of the matrix nylon was measured using gel permeation chromatography. The thermal-mechanical properties of the NA/MCN composites were characterized by thermo-dynamic mechanical analysis, and the results were compared with micro-Al2O3-reinforced nylon (MA/MCN) composites. A tensile property test was conducted to investigate the mechanical properties of neat nylon and composites. Experimental results showed that the average molecular weight of the matrix nylon filled with nano-alumina had little change and was higher than that with micro-alumina. The glass transition temperature (Tg) and storage moduli of NA/MCN composites were higher than that of neat nylon. During the experiment, it was also found that the tensile strength increased up to 52% when 3 wt.% of nano-Al2O3 particles were added. The thermal and tensile properties of NA/MCN composites were better than those of the MA/MCN composites when the same weight percentage of Al2O3 particles was used. 相似文献
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MC尼龙—碳纤维复合材料的制备 总被引:2,自引:0,他引:2
在单体浇铸尼龙的聚合过程中加入10%各向同性沥青基短切碳纤维,研究了温度及催化剂和活化剂用量对聚合的影响,结果表明:这些参数对聚合物相对分子质量影响很大,而空气湿度对聚合的干扰更为严重;对聚合物的性能测试显示:该尼龙导热系数明显提高,耐压缩性和抗弯曲性得到改善,抗冲击强度有所下降。 相似文献
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采用原位聚合反应制备MC尼龙/纳米CaSO4复合材料并对其性能、形貌和结晶形态进行了分析。分析结果表明:复合材料中纳米CaSO4达到了纳米级分散,起到同时增强增韧的作用,复合材料拉伸强度比MC尼龙提高17.4%;弯曲模量提高26.9%;冲击强度提高16.7%。纳米CaSO4的引入没有改变尼龙6的结晶形态;修饰后的纳米CaSO4有利于在MC尼龙中均匀分散。 相似文献
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ABSTRACT: Toluene-2,4-diisocyanate and dodecanol were used to chemically functionalize nanosilica (TDID-SiO2). Composites of TDID-SiO2 and oil-impregnated monomer casting nylon (OMC nylon) were prepared by an in situ anionic ring-opening polymerization. The dispersion of the TDID-SiO2 in oil was studied along with the mechanical and friction properties of the composites. The results show that the dispersion of the TDID-SiO2 in oil was significantly enhanced. Specifically, some TDID-SiO2 was wrapped in oil droplets, and the size of the oil droplets increased from 2.3 to 3.3 μm for 0–0.125 wt % of the TDID-SiO2 nanoparticles, which was confirmed by scanning electron microscopy. The composites exhibited excellent mechanical properties when 0.10 wt % TDID-SiO2 was integrated into OMC nylon. The tensile strength, elastic modulus, notched impact strength, flexural strength, and flexural modulus increased by 6.9%, 7.1%, 33.2%, 15%, and 77.5%, respectively, compared to OMC nylon without TDID-SiO2 nanoparticles. The friction coefficient was effectively controlled and the abrasion quantity was reduced. Thermogravimetric analysis showed that the thermal decomposition temperature was also improved. The improved mechanical and frictional properties of TDID-SiO2/OMC nylon composite will enhance its application in wear-resistant products in heavy industry. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 46994. 相似文献
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Preparation of compatibilizer with large specific surface and its application in immiscible polymer blends with ultra‐high molecular weight
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In this work, a compatibilizer (UHMWPE‐g‐GO) with large specific surface was prepared from graphene oxide (GO) and ultra‐high molecular weight polyethylene (UHMWPE). First, GO was modified by 2, 3‐epoxypropyltrimethylammonium chloride (GTA), subsequently grafted with UHMWPE. UHMWPE‐g‐GO was used to compatibilize the immiscible monomer casting (MC) nylon/UHMWPE blends. With the addition of very low content of UHMWPE‐g‐GO, the compatibility of UHMWPE and the matrix (MC nylon) was remarkably improved without visible agglomerates, which was proved by photographs, scanning electron microscope, dynamic thermomechanical analysis, and contact angle measurement. Therefore, thermal stability, mechanical and tribological properties were obviously increased. A dramatic increment of 94.1% in the impact strength and a decrement of 39.4% in the coefficient friction were observed in the presence of UHMWPE‐g‐GO in the immiscible polymer blends. The approach used in this work was an efficient strategy for immiscible polymer blends with ultra‐high molecular weight. POLYM. ENG. SCI., 57:335–344, 2017. © 2016 Society of Plastics Engineers 相似文献
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MC尼龙6/纳米SiO2复合材料的合成 总被引:2,自引:0,他引:2
用原位聚合法制备MC尼龙6/纳米SiO2复合材料。当纳米SiO2的加入量为1%时,力学综合性能最优。与纯MC尼龙相比,拉伸强度提高21%,弯曲模量提高40.3%,简支梁冲击强度提高69.1%,断裂伸长率降低43%。随着纳米SiO2含量的增加,复合材料的力学性能呈现减小趋势。采用SEM、XRD对产物进行了表征,表明采用修饰后的纳米SiO2加入到产物中,粒子分布均匀,粒径分布窄,粒子的粒径在30nm左右。随着纳米SiO2加入量的增加,MC尼龙6/纳米SiO2复合材料的结晶度下降。 相似文献
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根据阴离子聚合反应机理,通过解决催化剂及活化剂的配比,真空度的控制及聚合温度这些聚合过程中的主要问题,在静态浇铸条件下制备了单体浇铸尼龙,并通过测定聚合时间、转化率、拉伸强度、断裂伸长率、吸水率等指标的变化规律及联系来分析合成条件对高聚物的力学性能的影响。实验结果表明,当催化剂NaOH用量在0.6 mol/100 mol CPL(已内酰胺)时,其单体转化率最高。催化剂和活化剂对聚合时间、转化率及吸水率的影响规律均相似。在一定温度范围内,随着聚合温度的升高,转化率、拉伸强度及断裂伸长率增加。 相似文献
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MC尼龙/Sm2O3纳米复合材料的制备及性能研究 总被引:1,自引:1,他引:0
用原位分散聚合法制备了一系列MC尼龙/Sm2O3纳米复合材料,并对其结构和力学性能进行了表征.结果表明,纳米Sm2O3使MC尼龙晶格尺寸发生了一定程度的改变;纳米Sm2O3的加入可以明显改善MC尼龙的力学性能,对MC尼龙同时具有增强和增韧双重效果;MC尼龙/Sm2O3纳米复合材料的力学性能随着纳米Sm2O3用量的增加呈先升高后降低的趋势.当纳米Sm2O3的质量分数为0.5%时,复合材料的拉伸强度和断裂伸长率达到最大值,分别比MC尼龙提高了18.8%和91.5%,当纳米Sm2O3的质量分数为1.0%时,复合材料的缺口冲击强度、穹曲强度和弯曲弹性模量达到最大值,分别比MC尼龙基体提高了36.6%、11.2%和11.5%. 相似文献
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MC尼龙/CaCO3纳米复合材料的制备及力学性能研究 总被引:11,自引:4,他引:7
用超声分散原位聚合法制备了铸型(MC)尼龙/CaCO3纳米复合材料,用扫描电镜(SEM)对纳米CaCO3粒子在基体中的分散情况进行了表征,研究了纳米CaCO3用量对复合材料力学性能的影响。研究结果表明,纳米CaCO3对MC尼龙具有增韧和增强的双重效果,复合材料的拉伸强度和缺口冲击强度随着纳米CaCO3用量的增加先提高后降低,而断裂伸长率随着纳米CaCO3用量的增加而降低,当纳米CaCO3的用量为2%—3%时复合材料的综合性能最好。 相似文献
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Yanwen Zhao Qing Meng Qian Zhang Fan Wang Qin Wang Yuexin Wang 《Polymer Engineering and Science》2019,59(5):982-988
Oil‐impregnated monomer casting (OMC) nylon composites reinforced by graphene oxide and Lanthanum(III) chloride (LaCl3) were prepared by anionic ring‐opening polymerization in the presence of sodium hydroxide catalyst and toluene‐2, 4‐diisocyanate cocatalyst. The cross‐linked GO was formed by the coordination and electrostatic interactions between La3+ and the carboxyl on the edge of GO, which resulted in an obvious reinforcement for the OMC nylon composites. The effects of different rare earth contents on mechanical and tribological properties of the composites were carried out. The results showed that the composites exhibited excellent comprehensive properties when 0.01 wt% GO and 0.007 wt% LaCl3 were incorporated in OMC nylon. The elastic modulus, flexural strength, flexural modulus, compressive strength, notched impact strength, and elongation‐at‐break for the OMC nylon/GO/LaCl3 composites increased by 6.1, 9.9, 18.2, 7.2, 40.8, and 24.4%, respectively, and the tensile strength was slightly improved. In addition, the abrasion quantity was reduced. POLYM. ENG. SCI., 59:982–988, 2019. © 2019 Society of Plastics Engineers 相似文献