Crystallization Behavior Of PLLA/POSS Organic-inorganic Hybrid Materials

In recent years, polyhedral oligomeric silsesquioxane (POSS) has attracted a lot ofattentions among the inorganic nanocomposite materials, due to mechanical property, electricalproperties, thermal properties, optical properties, flame resistance, biocompatibility and so on.The high-performance POSS can improve the performance of PLA and broaden its applicationfields. For low mechanical strength, bad thermal property, slow degradation rate of PLA, weintroduce POSS nanocage into PLLA and systematically investigate the crystallization behaviorof the hybrid material.In this study, water-soluble POSS was synthesized via hydrolysis condensation. POSS-AHwas used to initiate ring-opening polymerization of lactide under microwave conditions, graftingpolylactic acid segment on POSS. And the segment length can be controlled by feed ratio ofPOSS-AH and lactide.Banded spherulites can be obtained from blends of hybrid materials and pure PLLA underproper conditions. Crystallizaed temperature and thickness of wafer are two critical factors forthe formation of banded spherulites. The interface colour of banded spherulites changes withthickness of wafer, covering all visible light wavelengths.Cracks can be observed in spherulites while cooling. For there is some relationship betweencracks and mechanical property, we study the influence of POSS on the cracks in spherulites,along with other key factors.