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Crystallization kinetics of poly(butylene terephthalate) (PBT): Influence of additives and free carboxylic acid chain ends
Author(s) -
Pillin Isabelle,
Pimbert Sylvie,
Feller JeanFrançois,
Levesque Guy
Publication year - 2001
Publication title -
polymer engineering and science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.503
H-Index - 111
eISSN - 1548-2634
pISSN - 0032-3888
DOI - 10.1002/pen.10720
Subject(s) - crystallization , materials science , talc , kinetics , nucleation , polymer chemistry , chemical engineering , polyester , shrinkage , composite material , organic chemistry , chemistry , physics , quantum mechanics , engineering
Degradation of poly(butylene terephthalate) (PBT) induced by blending time at 260°C leads to an increase of both carboxylic end groups and melt viscosity index and a decrease of the molecular weights. Crystallization kinetics of pure PBT and PBT blended with and epoxide, which was used to reduce the free carboxylic acid concentration, were compared. Lower carboxylic acid concentrations were obtained, but the molecular weights still decreased. The crystallization kinetics of PBT blended with pigments and/or mineral fillers were also studied. Dyes, some of which are known for their nucleation activity, were used for differentiating extruded PBT tubes in optical fiber loose cables. Post‐shrinkage appeared to depend on the type of pigment used. Pigments Concentration, particle size and chimical nature have been correlated to the PBT crystallization kinetics. An increase of the nonisothermal crystallization temperature was observed, more or less important according to the pigment used. Talc and mica were also tested in PBT blends, with and without pigments. Their mucleation activity parameters were measured and compared with those for the pigments. An average value of the crystallization temperature, nearly constant and independent of the Pigment, was obtain controlled shrinkage on industrial products with strict dimension requirements.