Study On Structure And Performace Of Poly(Butylene Succinate) Based Biopolymer Nanocomposites

The demand for environmental sustainability has resulted in a great interest in finding new materials that are biodegradable and environmentally friendly.Therefore,composites where the matrix and reinforcing phase are based on renewable resources have been the subject of extensive research.It is expected that cellulose nanocomposites will open new areas for applications in medicine,packaging,electronics,the automotive sector,construction and other areas.The disposal problem of waste petroleum-derived plastics and increasing environmental concerns have motived the development,production and application of biodegradable polymers.Recently,considerable interest has been attracted on the poly(butylene succinate)(PBS),one of the promising biodegradable material produced from renewable resources at relatively low cost and large production volume and combined advantages of good mechanical and thermal properties compared with other biodegradable material like polylactic acid(PLA).The polysaccharides nanoparticles such as chitin nanofibers(CNF)and chitosan nanofibers(CSF)which abundant in nature can be extracted from naturally occurring polymer.Chitin nanofibers and chitosan nanofibers have many excellent properties including biodegradability,biocompatibility and bioactivity,and thus they can be extensively studied.In this work,the polysaccharides nanoparticles will be used as nanofillers to reinforce the PBS matrix and then to prepare the biodegradable nanocomposites.The main research and conclusions are as follows:1.Chitin nanofibers have been prepared from crab shell as a chitin source using ultrasound assisted fibrillation.Transmission electron microscopy(TEM)study showed that the prepared rod-like nanofibers were having diameters and lengths primarily in the range of 20–60 nm and several micrometers respectively.In addition,it is confirmed the chitin nanofibers preserve the original chemical structure and crystalline structure via the results of Fourier transform infrared spectroscopy(FTIR)and X-ray diffraction(XRD).And then,PBS-based chitin nanofibers composites were prepared by the method of combining solution blending and hot pressing.The influence of the content of nanofibers on the mechanical properties,melt index of PBS-based chitin nanofibers blends was discussed by controlling the content of chitin nanofibers.The result of X-ray diffraction(XRD)show that the nanofibers didn't change the crystal style of PBS.What's more,the dispersity and compatibility of PBS and chitin nanofibers can be observed by the scanning electron microscopy of the composites cross-section.2.These chitin nanofibers were used as the precursor material for the preparation of chitosan nanoparticles and nanofibers.Deacetylation of chitin was achieved by treating chitin nanofiber dispersion with 50%(w/v)concentrated solution of NaOH.The degree of deacetylation of these prepared chitosan nanostructures were found to be approximately 87% via the result of alkali method and Fourier transform infrared spectroscopy(FTIR).In addition the result of X-ray diffraction(XRD)revealed that these chitosan nanostructures showed amorphous crystallinity.The diameter and the length of the chitosan nanofibers were found to be less than 100 nm and 3 ?m respectively by the transmission electron microscopy(TEM)images.PBS-based chitosan nanofibers composites were prepared by the method of combining solution blending and hot pressing as well.The chitosan nanofibers didn't change the crystallization of PBS via the results of X-ray diffraction(XRD).The scanning electron microscopy images of the composites cross-section revealed that chitosan nanofibers were well dispersed in PBS matrix,which help to develop the performance of composites in mechanical,thermal and processing.