当前位置：
X-MOL 学术
›
Macromolecules
›
论文详情
Our official English website, www.x-mol.net, welcomes your
feedback! (Note: you will need to create a separate account there.)
The Roles of Blending and of Molecular Weight Distribution on Craze Initiation
Macromolecules ( IF 5.1 ) Pub Date : 2017-11-20 00:00:00 , DOI: 10.1021/acs.macromol.7b01289 Andrea Sánchez-Valencia 1 , Olga Smerdova 1 , Lian R. Hutchings 2 , Davide S. A. De Focatiis 1
Macromolecules ( IF 5.1 ) Pub Date : 2017-11-20 00:00:00 , DOI: 10.1021/acs.macromol.7b01289 Andrea Sánchez-Valencia 1 , Olga Smerdova 1 , Lian R. Hutchings 2 , Davide S. A. De Focatiis 1
Affiliation
|
Craze initiation stress was measured in three-point bending isochronal creep tests on a series of entangled bimodal blends of polystyrenes of narrow dispersity, on three polystyrenes of broad dispersity, and on four blends of polystyrenes of broad dispersity. Crazing stress was found to increase rapidly with small additions of the higher molar mass component, quickly reaching a plateau. A simple model based on the weighted addition of the crazing stress contributions of the individual weight fractions obtained from an established piecewise linear crazing law was able to predict the crazing stress accurately in the bimodal blends using a power law exponent of 2.59 (90% CI [1.75–17.34]). In broad dispersity systems, in particular where short unentangled chains dilute the polymer, it was found necessary to modify the model using dynamic tube dilution theory. Dilution leads to a change in the entanglement length and hence in the molar mass at which transitions to disentanglement and chain scission crazing occur. With the improved model, crazing stress could be predicted even for the broad dispersity polymers with wide and bimodal distributions. This represents an opportunity for the molecular design of polymers by blending to achieve improved resistance to craze initiation.
中文翻译：
共混和分子量分布在热潮引发中的作用
在三点弯曲等时蠕变测试中，在一系列纠缠的窄分散聚苯乙烯双峰共混物，三种分散性较宽的聚苯乙烯和四种分散性较广的聚苯乙烯的共混物上测量了开裂初始应力。发现少量添加较高摩尔质量的组分时，裂纹应力会迅速增加，并迅速达到平稳状态。一个简单的模型基于加权重量的加权相加，该重量是从已建立的分段线性裂纹定律获得的各个重量分数的加权应力中得出的，使用功率定律指数为2.59（90％CI [ 1.75–17.34]。在广泛的分散体系中，尤其是短的无缠结链会稀释聚合物的情况下，发现有必要使用动态试管稀释理论对模型进行修改。稀释导致缠结长度发生变化，从而导致摩尔质量发生变化，在该摩尔质量处过渡到解缠结并发生断链裂纹。使用改进的模型，甚至可以预测具有宽峰和双峰分布的宽分散性聚合物的开裂应力。这代表了通过共混获得改善的抗开裂性的聚合物分子设计的机会。
更新日期：2017-11-20
中文翻译：
共混和分子量分布在热潮引发中的作用
在三点弯曲等时蠕变测试中，在一系列纠缠的窄分散聚苯乙烯双峰共混物，三种分散性较宽的聚苯乙烯和四种分散性较广的聚苯乙烯的共混物上测量了开裂初始应力。发现少量添加较高摩尔质量的组分时，裂纹应力会迅速增加，并迅速达到平稳状态。一个简单的模型基于加权重量的加权相加，该重量是从已建立的分段线性裂纹定律获得的各个重量分数的加权应力中得出的，使用功率定律指数为2.59（90％CI [ 1.75–17.34]。在广泛的分散体系中，尤其是短的无缠结链会稀释聚合物的情况下，发现有必要使用动态试管稀释理论对模型进行修改。稀释导致缠结长度发生变化，从而导致摩尔质量发生变化，在该摩尔质量处过渡到解缠结并发生断链裂纹。使用改进的模型，甚至可以预测具有宽峰和双峰分布的宽分散性聚合物的开裂应力。这代表了通过共混获得改善的抗开裂性的聚合物分子设计的机会。
京公网安备 11010802027423号