Study On Properties Of Polylactide/Aluminate Coupling Agent Modified Calcium Carbonate Blends

Polylactide?PLA?,with good biocompatibility and biodegradation,is a kind of environmentally-friendly polymer polymerized from lactic acid.Nevertheless,the application of PLA is limited due to its inherent brittleness,demanding condition of biodegradation and high cost.Therefore,improving the mechanical and biodegradable properties as well as reducing the cost of PLA is important and meaningful.The research focuses on the problems stated above and followed are the main experiments and conclusions.?1?The Al-CaCO₃ was successfully prepared,measured by FTIR,by modifying CaCO₃with Aluminate coupling agent?ACA?.?2?PLA/CaCO₃ and PLA/Al-CaCO₃ blends were prepared by melting blending and a series of tests were performed.Mechanical tests suggested that CaCO₃ reduced the toughness of PLA while Al-CaCO₃ increased.Biodegradation tests indicated that the addition of inorganic particles greatly improved the biodegradation properties of the blends,which is beneficial to home and industry compost.The fractured surfaces of the samples after notched impact strength were observed by scanning electron microscope?SEM?,it was found that the CaCO₃ particles were just located at the surface of PLA matrix while Al-CaCO₃ particles were buried into it,indicating that ACA is able to intensify the combination of PLA matrix and CaCO₃ particles,which consequently results in the toughness enhancements.?3?PLA/PDEGA/CaCO₃ and PLA/PDEGA/Al-CaCO₃ composites were prepared.Differential scanning calorimetry?DSC?tests and Polarizing microscope observation suggested PDEGA promoted the crystallization and improved the crystallinity of PLA.Biodegradation tests of Protease K indicated that the addition of PDEGA slightly suppressed the biodegradation properties of the blends while inorganic particles improved the degradation performance of the system,Al-CaCO₃ has a better effect than CaCO₃.?4?60/40 PLA/Al-CaCO₃ blend is named as PAC and PAC/ESO composites were prepared.Mechanical tests suggested 5%ESO toughened PAC blend best that the elongation at break of the composites was notably improved to 150%.DSC results indicated that ESO promoted the crystallization and improved the crystallinity of PLA.Rheological and Melting index?MI?tests demonstrated that the liquidity of the composites was increased with increasing of ESO content,which is beneficial to the actual processing of the composites.