Contribution to poly(m-xylylene adipamide) characterization: Hydrolysis, condensation, and oxidation in the melt
Contribution to poly(m-xylylene adipamide) characterization: Hydrolysis, condensation, and oxidation in the melt
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DOI：
10.1002/(sici)1099-0518(19960430)34:6
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发表时间：
1996-04
期刊：
影响因子：
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通讯作者：
B. Deroover;G. Coppens;J. Devaux;R. Legras;A. Momtaz
中科院分区：
文献类型：
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作者：
B. Deroover;G. Coppens;J. Devaux;R. Legras;A. Momtaz
PAmXD，6 [聚（间苯二甲酰己二胺）]使用Brabender塑性计在30 rpm和265 +/-5 ℃下加工。从溶液粘度和链端浓度测量确定的M（n）对混合时间的演变表明，PAmXD，6根据其初始分子量经历水解或缩合反应。较低的质量进行缩合，而较高的质量进行水解。在混合时间期间测定熔体中的水浓度证实，该行为与估计为500 +/-100的平衡常数有关。对于短于20分钟的混合时间，观察到由链端浓度或溶液粘度确定的M（n）值之间的良好对应性。然而，对于长于20分钟的混合期，使用两种方法的M（n）值之间的差异证明PAmXD的氧化降解的可能出现，6。从PA 6和PA 6，6的已建立的氧化反应改编的机制，提出证明PAmXD，6的行为。这些反应可以解释PAmXD，6在其加工过程中的轻微泛黄。还显示PAmXD，6 Brabender塑性计混合扭矩（30 rpm，265 +/-5 ℃）在log/log图中与M（n）线性相关。(C)John Wiley & Sons，Inc.
PAmXD,6 [poly(m-xylylene adipamide)] was processed using a Brabender plastograph at 30 rpm and at 265 +/- 5 degrees C. The evolution of the M(n) versus mixing time determined from solution viscosity and chain end concentrations measurements shows that PAmXD,6 undergoes hydrolysis or condensation reactions depending on its initial molecular mass. Lower masses undergo condensation while higher masses undergo hydrolysis. The determination of water concentration in the melt during mixing time confirmed that this behavior is related to an equilibrium constant which was estimated at 500 +/- 100. For a mixing period shorter than 20 min, a good correspondence was observed between M(n) values determined either by chain end concentrations or by solution viscosity. However, for a mixing period longer than 20 min, discrepancy between M(n) values using both methods witnesses the probable appearance of oxidative degradation of PAmXD,6. Mechanisms adapted from the established oxidation reactions of PA6 and PA6,6 are proposed to justify the PAmXD,6 behavior. Those reactions could explain the slight yellowing of PAmXD,6 during its processing. It was also shown that the PAmXD,6 Brabender plastograph mixing torque (30 rpm, 265 +/- 5 degrees C) is linearly related to M(n) in a log/log diagram. (C) 1996 John Wiley & Sons, Inc.