| PVA film is known as a popular research direction because of its special excellent characteristics in many aspects. e. g. water solubility and degradability. To develop new process technology and produce widely applied PVA film is an international issue. Starch is a kind of low cost, renewable and biodegradable materials. Adding starch into PVA can not only lower the cost but also promote the degradability. PVA/Starch films were continuously prepared by pelleting and bubble film technology. To promote the water resistance of the film, coupling agent, PLA and EAA were added into the blends. Heat treatment was also applied. Effects of mixing condition, starch content, plasticizer content and ratio of water/ plasticizer on melt fluidity, mechanical properties, water resistance and transmissivity were investigated. It was found that PVA/Starch blend would be well swelled and plasticized if the plasticizer was added in gradually and components were mixed between 80℃and 110℃. The optimal pelleting temperature was from 165℃to 180℃and the optimal bubble film temperature was from 205℃to 220℃. Melt fluidity was better when starch content was from 35% to 50%, plasticizer content was beyond 60 phr and ratio of water/plasticizer was from 1/6 to 1/3. Best mechanical properties were measured when the starch content was 40%, plasticizer was 60 phr and the water content was 33%. No.3 coupling agent can improve the mechanical properties and water resistance of the film and the best content was 3 phr. Heat treatment for 3 minutes at 150℃made contribution to water resistance. The transmissivity was influenced dramatically by the compatibility of PVA and starch, and peaked when the ratio of PVA and starch was 50/50. No. 3 coupling agent can improve the transmissivity of the film and the value was doubled when the content of coupling agent was 5 phr.
|
PDF Full Text Request