共查询到18条相似文献,搜索用时 875 毫秒
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建立了尼龙 6固相聚合过程动力学模型 ,并用实验数据进行了验证。考查了模型参数对固相聚合尼龙 6聚合度和多分散性指数的影响 ,分析固相聚合过程诸多的影响因素对尼龙 6聚合度及多分散性指数的影响。利用此模型 ,分析了固相聚合一定时间后水浓度、数均聚合度在颗粒半径方向上的分布 相似文献
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尼龙6固相聚合研究进展 总被引:4,自引:1,他引:3
对尼龙 6固相聚合方法与特点、工艺流程、动力学与机理的各种影响因素、粒子的粘结现象、模型化等进行了较系统综述 ,并提出了尼龙 6固相聚合模型化以及催化剂等需进一步研究的几点建议。 相似文献
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将聚醚型预聚体与己内酰胺单体共聚,制备单体浇铸尼龙(MC尼龙)/聚氨酯共聚物。研究了预聚体的异氰酸指数(R=—NCO/—OH)和预聚体质量分数对MC尼龙/聚氨酯共聚物的力学性能、维卡软化温度和结晶度的影响。结果表明:PPG和PTMG预聚体对MC尼龙的增韧效果较好,且PTMG预聚体在R=1.6、质量分数为10%时增韧效果最好,缺口冲击强度达到23.1kJ/m2。随聚氨酯预聚体质量分数的增加,MC尼龙的维卡软化温度逐渐下降,结晶度和熔点均降低。 相似文献
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由聚丙二醇与甲苯二异氰酸酯(TDI–80)反应,合成聚氨酯预聚体,以此预聚体活化己内酰胺单体,在催化剂Na OH作用下,引发己内酰胺单体聚合,制得预聚体增韧单体浇注尼龙(MCPA6)嵌段共聚物。改变预聚体添加量,可制得不同性能的嵌段共聚物。研究发现,随预聚体添加量的增加,嵌段共聚物材料的断裂伸长率升高,拉伸强度、硬度下降,而密度几乎无变化,表明预聚体对单体浇注尼龙增韧效果明显。 相似文献
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采用熔融缩聚法制备聚L-乳酸(PLLA)和聚D-乳酸(PDLA)预聚物;将相对分子质量相近的PLLA和PDLA预聚物分别溶于二氯甲烷中,进行溶液共混,制备部分或全部立构复合聚乳酸(sc-PLA);采用固相聚合的方法提高sc-PLA的相对分子质量,并对sc-PLA的结构和性能进行了表征。结果表明:sc-PLA的熔点比聚乳酸约高55℃,且与立构复合晶体结构有关;随着共混物中PLLA含量的增加,固相聚合后,scPLA的相对分子质量增加;立构复合结构的形成并不能提高sc-PLA的热降解温度,提高相对分子质量能明显提高sc-PLA的热稳定性,且相对分子质量越大,sc-PLA初始热降解温度越高,最高可达270℃。 相似文献
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Rangarajan Srinivasan Prashant Desai A. S. Abhiraman Raymond S. Knorr 《应用聚合物科学杂志》1994,53(13):1731-1743
This study is directed toward synergistic integration of processing of nylon 66 fibers with solid-state polymerization. The following two goals are sought through the incorporation of solid-state polymerization after the initial shaping operation: eliminating some of the processing problems in the production of high molecular weight, high performance industrial fibers and attainment of improved mechanical properties via high molecular weight. Successful solid-state polymerization has been achieved with as-spun fibers of nylon 66 and molecular weights up to 280,000 g/mol have been obtained from a starting molecular weight of 40,000 g/mol. It is shown that much of the ductility of the starting fiber can be retained, or even enhanced, with solid-state polymerization. Simulated drawing experiments using a thermal deformation analysis technique show an increase in the drawing potential of the solid-state polymerized fiber as compared to the starting material. This has important implications regarding the ultimate properties that can be achieved in fibers of condensation polymers. © 1994 John Wiley & Sons, Inc. 相似文献
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在一定假设基础上建立了尼龙6固相聚合过程模,并用实验数据验证了模型的正确性,结果表明随着固相聚合时间的延长,数均聚合度Un增加。 相似文献
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A low molecular weight prepolymer with reactive end groups was annealed at temperatures between 200 and 245°C to obtain kinetic parameters for solid-state polymerization of poly(ethylene naphthalate) (PEN). An equation was developed to describe the relationships among time, temperature, and final molecular weight for PEN. The intrinsic viscosity and melting point during polymerization were used to monitor the molecular weight and the thermal stability of the resulting resins. The effect of moisture concentration on solid-state polymerization was also investigated. Hydrolytic degradation caused initial reductions of the molecular weight if prepolymers were solid-stated without being dried. With increased exposure to solid-state conditions, however, the hydrolytically degraded resin dried and repolymerized at rates similar to those samples that had undergone hydrolysis. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2055–2061, 2001 相似文献
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为加深对聚己二酰己二胺(尼龙66)缩聚过程的理解,指导尼龙66生产过程的优化和新工艺开发,本研究基于聚合反应特性以及反应器流体力学特征,耦合聚合反应动力学模型、水-聚合物体系的汽液平衡模型以及传质模型,建立了尼龙66连续缩聚过程管式反应器和后缩聚反应器的数学模型,实现了尼龙66连续聚合过程的模拟。聚合物分子量及水含量的模拟值符合工业生产数据,验证了模型的可靠性,模拟分析了聚合工艺参数对聚合物分子量及水含量的影响,结果表明减少醋酸含量、提高反应器温度、降低管式反应器和后缩聚反应器压力均有利于快速提升聚合物分子量。较优的工艺条件为后缩聚器温度280~285℃,卧管式反应器压力1.600~1.750MPa。建立的模型准确性好,可用于考察工艺参数的影响,指导工业应用。 相似文献
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Haijie Li Yuting Shang Wenrui Huang Bingfeng Xue Xiaomeng Zhang Zhe Cui Peng Fu Xinchang Pang Qingxiang Zhao Minying Liu 《应用聚合物科学杂志》2021,138(39):51017
Succinic acid is an important synthetic monomer but it is difficult to use it as a precursor for synthesizing high molecular weight polyamide, due to its tendency to perform intra-cyclization reaction at high temperature. In order to solve this problem, in this paper, the direct solid-state polymerization (DSSP) method with the initial reactant, nylon salt which was composed of 1, 5-diaminopentane, succinic acid, and terephthalic acid, was applied to synthesize the bio-based copolyamide PA 5T/54. In comparison with the conventional melting polymerization method, the DSSP method can prevent the cyclization reaction of succinic acid effectively due to the lower reacting temperature as well as the restriction effect of the nylon salt. As a result, the product fabricated by DSSP method has higher molecular weight and much lighter color from red to white. Therefore, the DSSP method is advantageous for the synthesis of the polymers or copolymers composed of the succinic acid as the monomer. Furthermore, the polymerization mechanism proposed in this work can serve as a guidance for the design of the molecular structure and control of the polymerization process. 相似文献
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PA6固相聚合——相对分子质量研究 总被引:1,自引:1,他引:0
本文对PA6固相聚合(SSP)过程中影响聚合产物相对分子质量(RMW)的因素进行了研究.结果表明:RMW随RMW调节剂用量增加稍微增加后再迅速减小;聚合时间增加,则PA6的RMW开始迅速增加,随后逐渐减慢. 相似文献
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半芳香尼龙具有优异的力学强度、耐热性能和耐溶剂性能,在电子电器、汽车、轨道交通、特种装备中具有重要应用,受到了国内外学者和产业界的广泛关注。然而,传统聚合方法存在的制备周期长、分子量分布宽等技术难题长期得不到有效解决。本文利用微波能够使吸波材料快速、均匀升温的特点,首次在微波辅助条件下制备了耐高温半芳香尼龙PA12T,研究了在密闭条件下,以水作为吸波介质,水的用量、反应温度以及反应时间等条件对聚合产物特性黏数的影响,并对产物结构及热性能进行了表征。结果表明,微波辅助聚合与传统聚合方法相比,反应时间缩短三分之一以上,且产物分子量分布较窄,为解决传统半芳香尼龙聚合方法存在的问题进行了有价值的探索。 相似文献