Bioderived and Biodegradable Poly(3-hydroxybutyrate-<i>co</i>-3-hydroxyvalerate) Nanocomposites Based on Carbon Nanotubes: Microstructure Observation and EMI Shielding Property Improvement

Abstract

In view of the exhaustion of nonrenewable oil-based resources and the concerns on the environmental issues triggered by nondegradable plastics, biobased and biodegradable polymers have aroused increasing interest in recent decades. In this paper, bionanocomposites composed of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) as a matrix and carbon nanotubes (CNTs) as nanofillers were fabricated via a facile, green, and efficient method. Interconnected CNT structures and CNT–CNT networks formed in PHBV/CNT nanocomposites were demonstrated by a scanning electron microscope and transmission electron microscope. Compared with those of neat PHBV, the crystallization temperature and crystallinity of PHBV/CNT nanocomposites increased remarkably; in addition, the storage modulus increased by 6 orders of magnitude. A low electrical percolation threshold of 0.66 wt % was achieved in the PHBV/CNT nanocomposite. Furthermore, the dielectric and electromagnetic interference (EMI) shielding properties of PHBV/CNT nanocomposites were significantly improved with the increase of CNT content. For a typical PHBV/CNT sample with a thickness of 3 mm, the EMI shielding effectiveness reached 43.5 dB. The environmentally friendly PHBV/CNT nanocomposites prepared in this study were not only endowed with multifunctionality by the inclusion of CNTs but also made full use of the biogenetic derivation and biodegradability of the matrix to replace petroleum-based plastics and alleviate environmental pollution.