Structural characterization of PBT–LCP blends

• Published in: Materials letters 2002-10, Vol.56 (3), p.194-199
• Main Authors: Sahoo, N.G, Das, C.K, Pandey, K.N, Mathur, G.N
• Format: Article
• Language: English
• Subjects: Applied sciences; DMTA; DTA/TGA; Exact sciences and technology; Liquid crystalline polymer; Microstructure; Organic polymers; Physicochemistry of polymers; Polybutylene terephthalate; Properties and characterization; Structure, morphology and analysis; XRD
• ISSN: 0167-577X; 1873-4979
• DOI: 10.1016/S0167-577X(02)00439-1

Blends of polybutylene terephthalate (PBT) and thermotropic liquid crystalline polymer (LCP) have been prepared by melt mixing technique. Microstructures of the blends have been studied by XRD and SEM. Thermal properties and dynamic behavior of the composites have been analyzed by DTA/TGA and DMTA, respectively. From XRD, it is found that up to 20% LCP content nucleation is favored. Beyond this level of LCP, growth is favored. Interplanar distance remains almost unchanged. Thermal stability increases with increased the LCP content in the blends. Under dynamic application, at the lower level of LCP, the failure mechanisms are associated with deep cracks at different layers as observed from SEM. At the higher level of LCP, the failure, however, occurs at the glass fibre–matrix interfaces. The relaxation phenomenon as observed from DMTA analysis is changing depending on the blend ratio. At higher loading LCP, the relaxation peek shifts to the lower temperature side. The variation of storage modulus, loss modulus, stiffness and tan δ as a function of blend ratio suggested the phase inversion occurs at the blend ratio of 60:40 (PBT/LCP).