Theeraphol Phromsopha and Yodthong Baimark^*,

Biodegradable Polymers Research Unit, Department of Chemistry and Center of Excellence for Innovation in Chemistry, Faculty of Science, Mahasarakham University, Mahasarakham 44150, Thailand

*Corresponding author: Tel./Fax: +66 43 754246; E-mail: yodthong.b@msu.ac.th

Poly(L-lactide)-b-polyethylene glycol-b-poly(L-lactide) triblock copolymer (PLLA-PEG-PLLA)/exfoliated boron nitride (BN) composite films with different boron nitride contents (1, 2, 4 and 6 wt.%) were prepared by a solution-suspension casting method. Differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), X-ray diffractrometry (XRD) and tensile testing were carried out to characterize the thermal, morphological and mechanical properties of composite films. The DSC and XRD analyses showed the increasing crystallinity-content of composite films was obtained and their thermal stability as assessed by thermogravimetric analysis was improved when the boron nitride content was increased until 2 wt.%. Aggregation of boron nitride particles in composite films occurred when the boron nitride contents were higher than 2 wt.% as observed from SEM. The tensile stress of PLLA-PEG-PLLA film (25.0 MPa) increased up to 31.6 MPa while strain at break decreased from 76% to 64% when the 2 wt.% boron nitride was blended. Thus, PLLA-PEG-PLLA/BN composite films have potential to be used as flexible bioplastics.

Poly(lactic acid), Block copolymer, Boron nitride, Polymer composites, Mechanical properties.