Study On PHBH Packaging Films Modified By Graphene

Due to the defects in thermal,mechanical and other properties of green biodegradable plastics,the uses and population of them are limited.So it is necessary to improve the processing properties of theses materials,expand the applications and promote the sustainable development of green cycle ultimately.The purpose of the the paper is to explore the excellent technology for the preparation of PHBH packaging films by solution casting method.PHBH are modified by graphene and the final graphene/PHBH composite packaging films are tested by a series of characterization methods.The results show that:For pure PHBH packaging films,with the increase of drying temperature,the cross-sectional compactness,crystallinity,thermal stability,elongation at break and barrier properties increase firstly and then decrease.And the grain size gradually decreases,while the transparency and tensile strength gradually increase.When the drying temperature is 55℃,PHBH films have smooth section,high crystallinity,good thermal stability,mechanical strength and barrier.And the tensile strength,breaking elongation,oxygen permeability and water vapor permeability are 20.26 MPa,25%,116 cm3/m2·d and 29.23 g/m2·d,respectively.For graphene oxide/PHBH composite packaging film,with the increase of drying temperature,the dispersion of GO(graphene oxide),crystallinity,elongation at break and barrier of the composite films increase firstly and then decrease,while the tensile strength and transmittance increase with the increase of drying temperature.When the drying temperature is 45→55℃(gradient elevation of temperature),GO is dispersed uniformly in PHBH,and the cross section of composite films is smooth.And they have good crystallinity,thermal stability,mechanical and barrier properties.The tensile strength,elongation at break,oxygen permeability and water vapor permeability are 20.11 MPa,17.47%,48 cm3/m2·d,13.33 g/m2·d,respectively.The comprehensive properties of composite films are better than those of other composite films in other drying temperatures.For GO/PHBH composite packaging films,DSC and POM show that GO can increase the crystallinity and the spherulite number of PHBH,which indicating that GO plays a good role as nucleating agent in PHBH matrix.When the content of GO is 1.5wt%,the tensile strength and modulus of elasticity of composite packaging films are increased by 25%and 40%,respectively,compared with pure PHBH packaging films.And the oxygen permeability deceased by about 50%.Importantly,the transmittance of the composite packaging films can be reduced to 4.4%in the ultraviolet region,which is much lower than that of pure PHBH(81.8%),making the excellent ultraviolet resistance.For RGO(reduced graphene oxide)/PHBH composite packaging films,due to the reduction of Vitamin C,the surface resistance can be as low as 0.25 MΩ,which is much lower than that of pure PHBH packaging films(29 GΩ),making the excellent antistatic properties of composite packaging films.