Synergistic Modification Of PLA/PBAT With Insulating Particles And CNT

PLA/PBAT blends which is composed of Poly (lactic acid) and poly [(butylene adipate)-co-terephthalate], with excellent mechanical properties, better processing formability and biodegradability, is expected to be manufactured into biodegradable commodities and disposable medical supplies, to replace general engineering plastics (like PS) in order to ease the increasingly serious environmental problems. Some modifications in actual application are needed to improve its worse mechanical performance, thermal properties, and to prevent fire hazard resulted from the surface electrostatic charge which is hard to be dissipative. Thus methods for PLA/PBAT can improve intrinsic properties, reduce production costs and broaden application fields.Conductive materials reinforced by carbon nanotube (CNT) can integrate the advantages of CNT, like excellent specific strength and outstanding thermal conductivity, and embrace good antistatic property. But polymer only modified by CNT has certain limitations in the practical application for high costs of CNT and bad processing flowability. Blending materials, synergistically modified by insulating particles (mostly are organic montmorillonite OMMT and carbon black CB) and CNT, have already been developed, but there are few studies on synergistically modification efforts by using wollastonite and CNT. Besides, research was barely carried out about filling modification by mti-fillers (OMMT, wollastonite and CNT).On the basis of reasonable proportion of PLA/PBAT, the researches of PLA/PBAT/CNT (filled with OMMT and wollastonite) modifications were carried out in the paper. In addition, properties of PLA/PBAT/CNT filled with OMMT and CNT in different sequences were studied which were manufactured via twice extruding.Firstly, properties of PLA under different PBAT contents were studied, it was found that PBAT could reduce strength and flowability of PLA but improve the toughness and heat resistance, and component proportion of PLA/PBAT blends for subsequent researches was determined on the basis of comprehensive consideration of its properties. Also, the performance of PLA/PBAT with different OMMT contents was studied; it was found that OMMT could improve the strength and heat resistance of prepared composites.Secondly, the author studied the electrical performance and mechanical performance of PLA/PBAT with different CNT contents, synergistically modified by fillers of OMMT and CNT, also wollastonite and CNT separately. The results shown that appropriate content of CNT could improve the PLA/PBAT strength and stiffness. The author studied the performance of PLA/PBAT with different CNT contents, which were modified by three mixed fillers (0.1 wt% OMMT,2 wt% wollastonite and CNT), and found that volume resistivity of PLA/PBAT modified by mixed fillers (0.1 wt% OMMT,2 wt% wollastonite and 1.0 wt% CNT) dropped to below 107Ω·cm, which could meet the requirements of antistatic property.Lastly, using twice extruding, OMMT and CNT being added according to different sequences during mixing to modify PLA/PBAT, the blends’ mechanical properties and heat resistance with different CNT contents were studied. It was found that twice extruding process could improve the mechanical properties while it would decrease the heat resistance.