Tailor-Made Dispersion and Distribution of Stereocomplex Crystallites in Poly(L-lactide)/Elastomer Blends toward Largely Enhanced Crystallization Rate and Impact Toughness
Tailor-Made Dispersion and Distribution of Stereocomplex Crystallites in Poly(L-lactide)/Elastomer Blends toward Largely Enhanced Crystallization Rate and Impact Toughness
复制标题
聚（L-丙交酯）/弹性体共混物中立体络合物微晶的定制分散和分布，以大幅提高结晶速率和冲击韧性
DOI：
10.1021/acs.jpcb.7b03976
复制
发表时间：
2017
影响因子：
3.3
通讯作者：
Fu Qang
中科院分区：
文献类型：
--
作者：
Luo Yuanlin;Ju Yilong;Bai Hongwei;Liu Zhenwei;Zhang Qin;Fu Qang
聚(L-丙交酯) (PLLA) 和聚(d-丙交酯) 之间形成的立体络合物 (SC) 微晶作为环保型成核剂，在大幅提高 PLLA 基材料的结晶速率方面表现出巨大的潜力。然而，SC 微晶的成核效率仍然远低于预期水平，这主要是因为它们在 PLLA/PDLA 熔体中具有强烈的聚集倾向。在此，以 PLLA/聚（乙烯-丙烯酸甲酯-甲基丙烯酸缩水甘油酯）（E-MA-GMA）共混物为例，我们报告了一种独特而简便的策略，通过使用弹性体 E-MA-GMA 作为掺入 PDLA 的载体来控制 PLLA 基质中 SC 微晶的分散和分布。为此，首先将 PDLA 与 E-MA-GMA 混合或化学接枝到 E-MA-GMA 上。在后续PLLA与E-MA-GMA/PDLA母粒的熔融共混过程中，预分散在E-MA-GMA相中的PDLA链簇可以逐渐迁移到PLLA基体中，然后与基体链协同形成大量微小且分散良好的SC微晶。与PLLA和PDLA组分直接熔融共混形成的SC微晶团聚体相比，这种微小的SC微晶在加速PLLA基体结晶方面更加有效。更有趣的是，当PDLA链接枝到EMA-GMA上时，形成的SC微晶倾向于优先分布在共混物界面，因此不仅具有最佳的成核效率，而且具有优异的冲击韧性，因为这些界面局部的SC微晶还可以充当增强界面粘附力的桥梁。这项工作可以通过 SC 微晶的可控结构设计耐热和超韧 PLLA 共混物开辟一条新途径。
Stereocomplex (SC) crystallites, formed between poly(l-lactide) (PLLA) and poly(d-lactide), exhibit great potential to substantially enhance crystallization rate of PLLA-based materials as an eco-friendly nucleating agent. However, the nucleation efficiency of the SC crystallites is still far below an expected level, mostly on account of their strong aggregation tendency in PLLA/PDLA melts. Herein, taking PLLA/poly(ethylene-methyl acrylate-glycidyl methacrylate) (E-MA-GMA) blends as an example, we report a unique and facile strategy to control the dispersion and distribution of SC crystallites within the PLLA matrix by using elastomeric E-MA-GMA as carrier for the incorporation of PDLA. To do this, PDLA was first blended with E-MA-GMA or chemically grafted onto the E-MA-GMA. During subsequent melt-blending of PLLA and the E-MA-GMA/PDLA master batch, the PDLA chain clusters predispersed in the E-MA-GMA phase can gradually migrate into PLLA matrix and then collaborate with the matrix chains to form large amounts of tiny and well-dispersed SC crystallites. Compared with the SC-crystallite agglomerates formed by the direct melt-blending of PLLA and PDLA components, such tiny SC crystallites are much more effective in accelerating PLLA matrix crystallization. More interestingly, when PDLA chains are grafted onto the EMA-GMA, the formed SC crystallites tend to preferentially distribute at the blend interface and thus induce not only optimal nucleation efficiency but also superior impact toughness because these interface-localized SC crystallites can also serve as bridges to enhance interface adhesion. This work could open a new avenue in designing heat-resistant and supertough PLLA blends via controllable construction of SC crystallites.