Study On The Miscibility And Spinnability Of PHBV/PLA Blends For Melt-blown

At present, the main raw materials for melt-blown nonwovens are polyester (PET)and polypropylene (PP), this kind of petroleum base material is diffiult to recycle anddegrade when abandoned, and aggravate the environmental and energy problems. As agood measure to solve the white pollution, biodegradable material has become the hottopic in the material science. Poly (3-hydroxybutyrate-co-3-hydroxyvalerate)(PHBV)has drawn scientsts’ attention at home and abroad because of its excellentbiocompatibility and biodegradability, and the production process and degradationproducts are completely non-toxic, but the narrow processing window, poor thermalstability and large viscosity inhibit its application on melt-blown manufacturing.Poly(lactic acid)（PLA） is a kind of hot biodegradable material similar to PHBV，it has relative good thermal stability and spinnability for melt-blown.In this paper, PHBV and PLA blends were prepared with different proportion bymelt mixing, the structure and miscibility of blends had been researched including thecrystallization, thermal properties, thermodynamic performance and phasedistribution, the spinnability was also discussed including the rheology and theproperties of as-spun fiber. The influence of Tributyl Citrate (TBC) as compatibilizerand plastizer on the miscibility and spinnability of PHBV/PLA blends was alsoinvestigated. The results were shown as follows:1. PHBV/PLA blends showed two separate glass translation temperature（Tg）correspond to PHBV and PLA in the blends，PHBV/PLA blends showed differentmiscibility with different proportions but the miscibility between them was poor. Thephase interface in blends could be clearly distinguished and two phases appeared typical “sea-island” distribution with big difference on mix proportion while theblends showed continuous phase distribution with nearly mix proportion. It was notfound obvious chemical interaction between two components, PLA had obviousdilution effect on crystallization of PHBV but both of the crystal structure did notchange.2. The glass translation and melting temperature of PHBV/PLA blends decreasedwith the additive of TBC and the degree of decline was enhanced with the addingquantity increased, TBC showed good plasticizing effect on the blends. TBC made thetwo-phase interface get fuzzy, phase size decreased and dispersion evenness increased.TBC had an impact on the crystallization of PHBV/PLA blends, the crystalinity of thePHBV/PLA(25/75) blends decreased obviously and the crystallization velocity alsoreduced.3. The thermal stability and melting flowing rate of PHBV/PLA blends wereenhanced compared to pure PHBV, it could meet the processing requirement formelt-blown nonwovens, TBC had no significant effect on the thermal stability ofPHBV/PLA blends. PHBV/PLA melt was sensitive to the changes of temperature andshear rate that the apparent viscocosity decreased with the temperature and shear rateincreased and the spinnability of blends were improved with the PLA proportionincreased， the visicosity of PHBV/PLA blend melt increased when the additiveamount of TBC was low while the visicosity decreased when the amount increased.The drafting speed, surface flatness, degree of sticky of PHBV/PLA blends wereimproved with the PLA proportion increased but the degree of orientation was low,TBC improved the spinnability of PHBV/PLA blends, the melt drafting speed ofas-spun fiber increased, the surface becomed more smooth and the degree oforientation was improved but the sticky phenomenon was nearly not changed.