Salehiyan Reza, Ray Suprakas Sinha, Bandyopadhyay Jayita, Ojijo Vincent
DST-CSIR National Centre for Nanostructured Materials, Council for Scientific and Industrial Research, Pretoria 0001, South Africa.
Department of Applied Chemistry, University of Johannesburg, Doornfontein 2028, South Africa.
Polymers (Basel). 2017 Aug 9;9(8):350. doi: 10.3390/polym9080350.
The present work investigates the distribution of nanoclay particles at the interface and their influence on the microstructure development and non-linear rheological properties of reactively processed biodegradable polylactide/poly(butylene succinate) blend nanocomposites. Two types of organoclays, one is more hydrophilic (Cloisite30B (C30B)) and another one is more hydrophobic (Betsopa (BET)), were used at different concentrations. Surface and transmission electron microscopies were respectively used to study the blend morphology evolution and for probing the dispersion and distribution of nanoclay platelets within the blend matrix and at the interface. The results suggested that both organoclays tended to localize at the interface between the blend's two phases and encapsulate the dispersed poly(butylene succinate) phase, thereby suppressing coalescence. Using small angle X-ray scattering the probability of finding neighboring nanoclay particles in the blend matrix was calculated using the Generalized Indirect Fourier Transformation technique. Fourier Transform-rheology was utilized for quantifying nonlinear rheological responses and for correlating the extent of dispersion as well as the blend morphological evolution, for different organoclay loadings. The rheological responses were in good agreement with the X-ray scattering and electron microscopic results. It was revealed that C30B nanoparticles were more efficient in stabilizing the morphologies by evenly distributing at the interface. Nonlinear coefficient from FT-rheology was found to be more pronounced in case of blends filled with C30B, indicating better dispersion of C30B compare with BET which was in agreement with the SAXS results.
本工作研究了纳米粘土颗粒在界面处的分布及其对反应加工的可生物降解聚乳酸/聚丁二酸丁二醇酯共混纳米复合材料微观结构发展和非线性流变性能的影响。使用了两种类型的有机粘土，一种亲水性更强（Cloisite30B（C30B）），另一种疏水性更强（Betsopa（BET）），并采用了不同的浓度。分别使用表面和透射电子显微镜来研究共混物形态演变以及探测纳米粘土片层在共混物基体和界面处的分散和分布情况。结果表明，两种有机粘土都倾向于定位在共混物两相之间的界面处，并包裹分散的聚丁二酸丁二醇酯相，从而抑制聚并。使用小角X射线散射，通过广义间接傅里叶变换技术计算了在共混物基体中找到相邻纳米粘土颗粒的概率。利用傅里叶变换流变学来量化非线性流变响应，并关联不同有机粘土负载量下的分散程度以及共混物形态演变。流变响应与X射线散射和电子显微镜结果吻合良好。结果表明，C30B纳米颗粒通过均匀分布在界面处，在稳定形态方面更有效。发现填充C30B的共混物中傅里叶变换流变学的非线性系数更为显著，这表明与BET相比，C30B的分散性更好，这与小角X射线散射结果一致。
