College of Food Science and Technology, Huazhong Agricultural University, Wuhan 430070, PR China.
Fisheries Research Institute, Wuhan Academy of Agricultural Sciences, Wuhan, Hubei 430207, PR China.
Int J Biol Macromol. 2020 Oct 15;161:44-58. doi: 10.1016/j.ijbiomac.2020.06.011. Epub 2020 Jun 5.
In this study, we evaluated the possibility of dimethyldidodecylammonium bromide (DDAB)-modified graphene oxide quantum dots (DDAB-GOQDs) as a new compatibilizer to improve the compatibility of hydrophilic starch with hydrophobic polylactic acid (PLA) and ethylene-vinyl acetate-glycidylmethacrylate (EVA-GMA). The successful synthesis of DDAB-GOQDs was verified by Fourier transform infrared spectroscopy (FTIR), Transmission electron microscopy (TEM) and Zeta-Plus assay. The differential scanning calorimetry (DSC), polarized light optical microscopy (POM) and iso-thermal crystallization kinetics analysis showed that 0.25% DDAB-GOQDs could significantly increase the crystallization rate and nucleation density as well as reduce the spherulites size of the nanocomposites. Compared to pure composites, the nanocomposites containing 0.25% DDAB-GOQDs showed obvious enhancement in thermal stability and surface hydrophobicity, with an increase of ~22 °C and ~24.1° in the maximum decomposition temperature and contact angle, coupled with similar improvement in the storage modulus and UV-shielding capacity. Morphological analysis, FTIR and creep behavior experiments revealed that adding 0.25% DDAB-GOQDs enhanced the interface compatibility of the nanocomposites by promoting the formation of the interpenetrated network through strong polar hydrogen bond or electrostatic force within the polymeric components. Overall, (0.25%) DDAB-GOQDs can serve as an effective compatibilizer for the PLA/starch/EVA-GMA system due to improved crystallization, thermal stability, barrier properties and creep-resistance.
在这项研究中，我们评估了二甲基双十二烷基溴化铵（DDAB）修饰的氧化石墨烯量子点（DDAB-GOQDs）作为一种新型增容剂的可能性，以提高亲水性淀粉与疏水性聚乳酸（PLA）和乙烯-醋酸乙烯酯-甲基丙烯酸缩水甘油酯（EVA-GMA）的相容性。傅里叶变换红外光谱（FTIR）、透射电子显微镜（TEM）和 Zeta-Plus 分析验证了 DDAB-GOQDs 的成功合成。差示扫描量热法（DSC）、偏光显微镜（POM）和等温结晶动力学分析表明，0.25% DDAB-GOQDs 可以显著提高纳米复合材料的结晶速率和成核密度，降低球晶尺寸。与纯复合材料相比，含有 0.25% DDAB-GOQDs 的纳米复合材料表现出明显的热稳定性和表面疏水性增强，最大分解温度和接触角分别提高了约 22°C 和 24.1°，同时存储模量和紫外线屏蔽能力也有类似的提高。形态分析、FTIR 和蠕变行为实验表明，添加 0.25% DDAB-GOQDs 通过在聚合物成分内形成强极性氢键或静电力促进互穿网络的形成，增强了纳米复合材料的界面相容性。总的来说，（0.25%）DDAB-GOQDs 可以作为 PLA/淀粉/EVA-GMA 体系的有效增容剂，因为其提高了结晶性、热稳定性、阻隔性能和抗蠕变性。
