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Blends of thermotropic liquid crystalline polyesters and poly(butylene terephthalate): Thermal, mechanical, and morphological properties
Author(s) -
Chang JinHae,
Jo ByungWook,
Jin JungIl
Publication year - 1995
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.760352006
Subject(s) - materials science , thermotropic crystal , ultimate tensile strength , mesogen , composite material , polyester , alkoxy group , copolyester , polymer , polymer chemistry , liquid crystalline , organic chemistry , alkyl , chemistry
Blends of poly(butylene terephthalate) (PBT) with three different thermotropic liquid crystalline polyesters (TLCPs) were prepared. The first TLCP (HBH‐6) consists of diad aromaticester type mesogenic units and the hexamethylene spacers along the main chain, and the second (TB‐S6) is a wholly aromatic polyester TLCP having alkoxy side groups on the terephthaloyl moiety. The last (TR‐4,6) is an LC copolymer comsisting of triad aromatic ester type mesogenic units and two differents spacers; tetramethylene and hexamethylene units. Blends of TLCP with PBT were melt spum at different LCP contents and differnt draw ratios to produce monofilaments. For the HBH‐6/PBT and TB‐S6/PBT blends, the ultimate tensile strength showed a maximum value at the 5 wt% level of LCP in the blends, and then it decreased when the LCP content was increased up to 20%. On the other hand, the initial modulus monotonically increased with increasing LCP content in all cases. The blends with TB‐S6 showed the highest tensile properties of the three blends systems. This can be ascribed to the highest rigidity of the polymer chain, which still carries relatively long alkoxy substituents that promote sufficient adhesion between the LCP and PBT matrix. When compared with the PBT fiber itself, the fibers obtained from the 5% TB‐S6/PBT blends exhibited an improvement in tensile strength by > 25% and in tensile modulus by ∼ 200%.