Mechanical behavior and optical transparency of polyamide 6 of different morphology formed by variation of the pathway of crystallization
Mechanical behavior and optical transparency of polyamide 6 of different morphology formed by variation of the pathway of crystallization
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DOI：
10.1007/s00289-013-1079-9
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发表时间：
2014-03
期刊：
影响因子：
3.2
通讯作者：
I. Kolesov;D. Mileva;R. Androsch
中科院分区：
文献类型：
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作者：
I. Kolesov;D. Mileva;R. Androsch
研究了聚酰胺6（PA 6）在不同冷却速率下熔融结晶和不同温度下冷结晶的相组成和超分子结构，并将其与透光性、刚度和应力-应变行为联系起来。根据最高退火温度，冷结晶导致γ-中间相或α-晶体的非球晶形成。中间相和晶体均为球状。低过冷度下熔体结晶形成片状α晶和球晶，而高过冷度下形成球状中间相。在冷结晶的PA 6膜中不存在球晶导致高的透明透明度，这与具有不透明外观的缓慢熔融结晶的样品形成对比。虽然杨氏模量和玻璃化转变温度随着结晶度的增加而增加，但对于相同结晶度的样品，如果晶体是层状的而不是结节状的，则刚度相当高。较高的玻璃化转变温度的冷结晶PA 6是一个更高的刚性非晶部分比在熔融结晶的样品指向一个更强的耦合的非晶相有序域。
The phase composition and supermolecular structure of polyamide 6 (PA 6) melt-crystallized on cooling at different rates or cold-crystallized at different temperatures were characterized and related to the optical transparency, stiffness and the stress–strain behavior. Cold-crystallization results in non-spherulitic formation of γ-mesophase or α-crystals, depending on the maximum annealing temperature. Both mesophase and crystals are of nodular shape. Melt-crystallization at low supercooling leads to formation of lamellar α-crystals and spherulites, while at high supercooling the nodular mesophase is forming. The absence of spherulites in cold-crystallized PA 6 films leads to high see-through clarity which is in contrast to the slowly melt-crystallized samples with opaque appearance. While Young’s modulus and the glass transition temperature increase with increasing crystallinity, for samples of identical crystallinity stiffness is considerably higher if the crystals are of lamellar rather than of nodular shape. The higher glass transition temperature of cold-crystallized PA 6 is related to a higher rigid amorphous fraction than in melt-crystallized samples pointing to a stronger coupling of the amorphous phase to ordered domains.