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Sodium Hexametaphosphate‐Modified Thermoplastic Starch Materials Prepared with the Assistance of Supercritical CO 2
Author(s) -
Mi Siyu,
Sun Liangshuang,
Runt James,
Kuo Muchen,
Huang Kuoshien,
Yeh Jentaut
Publication year - 2020
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.201900055
Subject(s) - sodium hexametaphosphate , materials science , thermoplastic , chemical engineering , supercritical fluid , polymer chemistry , chemistry , composite material , organic chemistry , sodium , engineering
This paper describes sodium hexametaphosphate (SHMP)‐modified thermoplastic starch (TPS) resins (scCO 2 TPS 100 SHMP x ) gelatinized and/or modified with the aid of supercritical carbon dioxide (scCO 2 ). TPS and scCO 2 TPS 100 SHMP x exhibit considerably higher melt flow rates, moisture resistance, and initial and retention tensile strength values than TPS and TPS 100 SHMP x prepared using conventional atmospheric pressure. Only V h ‐type crystals are found in conditioned scCO 2 TPS 100 SHMP x , which show significantly lower melting temperatures (≈19 °C) than the corresponding conditioned TPS 100 SHMP x . Relative to TPS 100 SHMP x , conditioned scCO 2 TPS 100 SHMP x show a weaker hydrogen bonding network among the hydroxyl groups in the amylopectin chains and considerably less retrogradation. The loosely hydrogen‐bonded hydroxyl groups found in conditioned scCO 2 TPS 100 SHMP x can be replaced with stronger hydrogen bonds involving the phosphate groups of SHMP through the proper modification of scCO 2 TPS 100 SHMP x .