Synthesis And Characterization Of Poly Butyl Acrylate/starch Interpenetrating Polymer Networks

Interpenetrating polymer net-work(IPN) is a useful technique for designing materials with a wide variety of properties.It is an intimate combination of two polymers both in the network form.Starch is the abundant and renewable resource in nature that is non-toxic and biodegradable.Starch-based biodegradable plastic is one of the focuses of research in the field.In this paper,poly-butyl acrylate(PBA)/starch blends were synthesized by IPN technology and a series properties of blends were tested.The poly(butyl acrylate-co-acrylic acid)s were prepared by emulsion polymerization. Starch was prepared in water by heating at 90℃for 0.5h.To this starch solution, emulsion was added.Then make the blends to the Teflon mold to casting a film directly or modified the blends to obtain semi-IPN or IPN film.The influence of AA,starch, glycerol,aldehyde content,dialdehyde starch content,available chlorine content and oxidized starch content was investigated on mechanical properties,water absorption, biodegradable,thermal and dynamic mechanical properties of the films.The main results are summarized as follows:1.The water absorption ratio of the modifided starch blends was higher than starch blends.Mechanical properties of the blends were improved when acrylic acid and glycerol were added.There were highest tensile strength and elongation of the film with 10%acrylic acid and 4%glycerol.The mechanical properties of the modified starch blends were obviously better than starch blends which noted that the modified starch and PBA had the interpenetrating network strcture.The test showed that the crosslinking degree of the films were basically the same.2.Thermal properties were examined using differential scanning calorimetry(DSC) and Thermogravimetry(TG).The stability of the blends became better when acrylic acid and PBA were added.Because of the interpenetrating network of PBA/modified starch were formed,the starbility of the blends were improved.3.The damping properties of modifide starch/PBA blends were investigated by dynamic mechanical analyzer(DMA) which showed that the Tg of the blends were higher than pure PBA.The Tg of the oxidized starch blend was-17.9℃,and the damping functional temperature ranged with tanδ＞0.3 was 102℃that the damping properties was better than the dialdehyde starch blend which Tg was-18.294℃,and the damping functional temperature ranged with tanδ＞0.3 was 47.5℃.The micro-morphology and structure of starch and modifided starch blends were characterized by TEM.It showed that the compatibility of modifided starch blends were better than starch blends and the compatibility of oxidized starch blends was the best.This IPN structure improved the damping properties.4.The biodegradation ratio of the starch/PBA and oxidized starch/PBA film can exceed 60%in the soil after 25 days.The biodegradation ratio of the dialdehyde starch/PBA film can exceed 60%in the soil after 50 days.