Influence of oxidized polyethylene wax (OPW) on the mechanical, thermal, morphological and biodegradation properties of PHB/LDPE blends
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Blends of poly(β-hydroxybutyrate) (PHB) and low density polyethylene (LDPE) were prepared in proportions of 100/0, 75/25, 50/50, 27/75 and 0/100 (PHB/LDPE wt.%), with and without oxidized polyethylene wax (OPW, 5 wt.%), and the mechanical, thermal (differential scanning calorimetry and melting flow index, morphological (scanning electron microscopy) and biodegradation (aging in simulated soil) properties were evaluated. The addition of OPW increased the tensile strength and Young’s modulus but decreased the elongation at break of the blends. Similarly, OPW increased the Tg of the pure LDPE and enhanced the melt flow index. Scanning electron microscopy showed that OPW reduced the phase separation of LDPE and increased the biodegradation during aging in simulated soil.
KeywordsTensile Strength Differential Scanning Calorimetry Biodegradation LDPE LLDPE
The authors thank Braskem S.A., PHB Industrial S.A. and Megh Indústria e Comércio Ltda. for supplying the materials. This work was supported by CNPq (grant no. 304577/2004-9), FAPESP (grant no. 02/13202-6), CAPES and the Universidade São Francisco. The SEM work was done with the JSM-5900LV microscope in the Laboratório de Microscopia Eletrônica at the Laboratório Nacional de Luz Síncrotron (LME/LNLS), Campinas, SP, Brazil.
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