Poli (laktik asit) / barit kompozitlerinin hazirlanmasi ve karakterizasyonu

Interfacial adhesion between additive and polymer matrix plays a significant role in properties of polymeric composite materials. Surface of barite (BR) mineral was modified by silane coupling agent in order to increase compatibility between mineral additive and poly (lactic acid) (PLA) matrix. Surface properties of BR samples were characterized by Infrared spectrometry (IR). Untreated and surface silanized BR were compounded with PLA at the loading ratios of 5, 10, 15, and 20 wt% using melt-mixing process. Mechanical, thermomechanical, water resistance, melt flow, and morphological characterizations of composites were performed by tensile and impact tests, dynamic mechanical analysis (DMA), water absorption test, melt flow rate (MFR) test, and scanning electron microscopy (SEM) analysis, respectively. According to results, BR additions led to increase in tensile strength and tensile modulus of PLA. The maximum improvement was obtained for 15 wt% of silanized BR filled composite. Impact strength of composites increased with addition amount of BR. DMA analysis revealed that glass transition temperature of PLA extended to higher values by the addition of BR. Inclusions of BR caused slight decrease in MFR value of PLA. Silanized BR containing composites displayed lower water absorption values compared to untreated BR, thanks to hydrophobic nature of silicon coated surface. According to SEM micro-images of composites, more homogeneous dispersion in PLA matrix was observed for treated BR particles than untreated ones due to enhancement for interfacial adhesion of BR to PLA after silanization. Silanized BR was found to be suitable for the applications of PLA-based composites.