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Properties of Starch Films and their Improvement
Author(s) -
Takahashi Reiji,
Nakamura Atsushi
Publication year - 1970
Publication title -
starch ‐ stärke
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.62
H-Index - 82
eISSN - 1521-379X
pISSN - 0038-9056
DOI - 10.1002/star.19700220906
Subject(s) - polyvinyl alcohol , starch , urea , ultimate tensile strength , elongation , materials science , chemical engineering , modified starch , composite material , polymer chemistry , nuclear chemistry , chemistry , organic chemistry , engineering
The tensile strengths and elongations of starch films prepared from various unmodified and modified starches were measured. These properties were improved by addition of urea and polyvinyl alcohol to the starch paste. The results obtained were as follows.1 The heating temperature greatly affected the tensile strength and elongation of various unmodified starches. Potato starch gave the best film. 2 Introduction of hydroxyethyl groups into corn starch had unexpectedly little affect on the properties of the films. 3 A combination of hydroxyethylation and acid‐modification slightly improved the properties of the films. 4 No film could be obtained after combinations of hydroxyethylation and hypochlorite‐oxidation, pyrodextrinization or α‐amylase‐dextrinization. However, addition of urea to these modified starches resulted in good films. 5 On addition of urea the elongation of starch films increased and the pastes adhered uniformly to water repellent surfaces. 6 A film with the best properties was prepared from a mixture of 67% acid‐modified hydroxyethyl starch, 13% urea and 20% polyvinyl alcohol.