高速攪拌對澱粉／聚乙烯醇共混物溶液成膜性能的影響*
曾祥成 劉白玲 李坤福
摘 要 澱粉與聚乙烯醇(PVA)溶液在高速攪拌下共混，可大大改善澱粉／PVA共混薄膜的力學性能、透明性與耐水性，對其生物降解性有明顯的影響.澱粉／PVA共混體系在高速攪拌前后的光譜分析、顯微觀察、分子量及流變性能的測定表明，這些變化起因于高速攪拌增加了澱粉中直鏈澱粉的含量，同時提高了澱粉與PVA共混溶液的穩定性，改善了澱粉／PVA共混物薄膜的使用性能.
關鍵詞 澱粉，聚乙烯醇，高速攪拌，共混
EFFECT OF HIGH SPEED STIRRING ON
THE
PROPERTIES OF STARCH/PVA BLEND SOLUTION
ZENG Xiangcheng, LIU Bailing, LI Kunfu
(State Key Laboratory of Polymer Material Engineering,
Polymer Research Institute of Sichuan Union University,Chengdu 610065)
Abstract Polyvinyl
alcohol (PVA) can be degraded by bacteria from various soil sources and its
structure is somewhat similar to that of starch.It is an available way of
blending polyvinyl alcohol (PVA) with starch to develop biodegradable
materials.The high speed stirring is a suitable method while blending of PVA and
starch to prepare the biodegradable materials with better properties
required.The effect of high speed stirring on the properties of starch/PVA blend
solution was studied by means of spectrophotometry,microscopy,molecule weight
analysis and rheometry etc.The experimental results indicate that changes are
found on the chains of PVA and starch after conducting high speed stirring,which
causes a modification in the properties of starch/PVA blend solution.The
degrading effect of high speed stirring on starch and PVA agrees to the common
mechano-chemical degrading feature.The high speed stirring breaks the side chain
of starch and eventually increases the amylose content in starch solution.The
high speed stirring also lowers the Mw and widens the Mw
distribution of PVA.The dispersion of starch in PVA is improved by high speed
stirring and the interaction between starch and PVA is strengthened,resulting in
an improvement of the mechanical properties,transparency and water-repellence of
starch/PVA blend film.
Key words Polyvinyl
alcohol, Starch blend solution, High speed stirring