LIAO Kairong, LU Zejian, LI Hongquan. ENHANCEMENT OF POLY(L-LACTIDE) BY FIBRILLATED COMPRESSION MOLDING[J]. Acta Polymerica Sinica, 2000,(3):335-339.DOI:
Poly(L-lactide) (PLLA) rods with high strength were prepared by fibrillated compression molding in a special mold designed for this purpose.It was showed that this compression molding method had a great effect on enhancement of the mechanical strength of the molded materials. PLLA rods (∮3.2mm) with bending strength and shear strength of 250~280 MPa and 170~185 MPa respectively were obtained by using PLLA materials of molecular weight (Mv) ranged from 53×104 to 76×104 and compression molding at 140℃.The molecular weight of PLLA reduced by 65% to 70% in the process of preparing billets due to its thermal instability
but the influence of compression molding on the molecular weight was not significant.SEM observation showed thatthe PLLA billet underwent oriented deformation and formed fibrous structure during compression molding
and this is the reason why the mechanical strength of the PLLA rods can be enhanced.Analytical results of differential scanning calorimetry (DSC)and X-ray diffraction (XRD) indicated that after compression molding
the melt temperature of PLLA crystals decreased while the degree of crystallinity increased.