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Influence of heat treatment and fillers on the heat distortion temperature (HDT) of poly(lactic acid) hybrid biocomposites was intensively studied through HDT testing, polarizing microscope (POM), differential scanning calorimetry (DSC), and dynamic mechanical analysis (DMA). With loading 20 wt % BF or 20 wt % talc, improvement of HDT in PLA composite was about 10 C comparing with neat PLA after heat treatment. Moreover, there was a great improvement (above 45 C) of HDT in PLA composites with loading 20 wt % BF and 20 wt % talc simultaneously after heat treatment. Transcrystallization was observed during heat treatment and isothermal crystallization of PLA composites with loading BF and talc simultaneously. There was no similar phenomenon in other PLA composite with loading only one filler. The possible mechanism of forming transcrystallization was proposed. DSC and DMA were also used to clarify the variation in HDT before and after heat treatment, and the results suggest that the crystallinity, modulus and glass transition changed, especially formation of transcrystallization played a key role in improvement of HDT in PLA composites.

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This article reports on the relationship between the variation of hydrogen bonding and macroscopic properties of composites composed of hydrogenated nitrile butadiene rubber (HNBR) and 3,9‐bis {1,1‐dimethyl‐2 [β‐(3‐tert‐butyl‐4‐hydroxy‐5‐methylphenyl) propionyloxy] ethyl}‐2,4,8,10‐tetraoxaspiro [5,5]‐undecane (AO‐80). Hydrogen bonding of the composites was studied by Fourier‐transform infrared (FT‐IR) and ultraviolet (UV) spectroscopies. FT‐IR spectra at room temperature revealed that the stretching vibration peak of OH and CO of AO‐80 red shifted with increasing AO‐80 content, whereas that of C≡N of HNBR blue shifted only when the AO‐80 content exceeded 10 parts per 100 resin (phr). At elevated temperatures, the shift was the opposite for CO and C≡N bands resulting from hydrogen bonding dissociation. In the UV spectra, the E2 band of benzene ring of AO‐80 exhibited two peaks differing in shape. POLYM. ENG. SCI., 2011. © 2010 Society of Plastics Engineers

In this study, miscibility and dynamic mechanical properties of hydrogenated nitrile butadiene rubber (HNBR) and 3,9‐bis{1,1‐dimethyl‐2‐[β‐(3‐tert‐butyl‐4‐hydroxy‐5‐methylphenyl) propionyloxy]ethyl}‐2,4,8,10‐tetraoxaspiro[5,5]‐undecane (AO‐80) composites were investigated. The composites with low‐AO‐80 content showed the incomplete miscibility, and a part of AO‐80 dissolved into HNBR, while the rest was dispersed into HNBR in the form of deep‐submicron‐sized microspheres based on the micromorphological and thermal analyses. However, with the increasing AO‐80 content, the system became completely miscible. When blending with AO‐80, the resulting composite exhibited the remarkably improved dynamic mechanical property. The loss tangent (tan δ) peak of the composites gradually shifted to room temperature with the increasing AO‐80 content. In this work, two classical equations (Gorden‐Taylor and Fox) were used to predict the glass transition temperature of the HNBR/AO‐80 composites. The calculated value based on Fox equation was more close to the experimental data. POLYM. ENG. SCI., 2010. © 2010 Society of Plastics Engineers