Premium
Batch foaming poly(vinyl alcohol)/microfibrillated cellulose composites with CO 2 and water as co‐blowing agents
Author(s) -
Zhao Na,
Zhu Changwei,
Howe Mark Lun,
Park Chul B.,
Li Qian
Publication year - 2015
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.42551
Subject(s) - vinyl alcohol , materials science , blowing agent , composite material , cellulose , crystallinity , nucleation , supercritical fluid , supercritical carbon dioxide , composite number , plasticizer , chemical engineering , morphology (biology) , biopolymer , polymer , chemistry , polyurethane , biology , engineering , genetics , organic chemistry
ABSTRACT We studied the foaming behavior of poly(vinyl alcohol) (PVOH) and microfibrillated cellulose (MFC) composites in a batch process using supercritical carbon dioxide (scCO 2 ) and water as co‐blowing agents. In PVOH/MFC composites, water is an economical plasticizer. It not only suppresses the potential thermal degradation of PVOH but also extends the processing window. A uniform cell structure and a high cell density were achieved in the PVOH/MFC foams. The results showed that cell density was increased by increased water content. Further, the MFC contained both micro‐ and nano‐sized fibers. These created numerous heterogeneous nucleation sites and caused local pressure variations. However, cell density decreased when the MFC was overdosed. Due to the high crystallinity that then developed around the MFC, the gas content was too low, and the stiffness was too high. The experimental results also showed that the cell morphology and density could both be controlled by the water and the MFC content. The effects of the foaming temperature and pressure on the cellular morphology of the PVOH/MFC composite foams were examined systematically. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132 , 42551.