Ternary composites based on HDPE and Mater-Bi reinforced with hemp fibres: Study of the non-isothermal crystallization

Abstract

The non-isothermal crystallization process of biodegradable thermoplastic matrix (Mater-Bi®, MB) and traditional thermoplastic (high-density polyethylene, polyethylene, PE) blends was studied using differential scanning calorimetry (DSC). Hemp fibres were used as filler, and maleic anhydride-functionalized high-density polyethylene ( m{PE^{∗}}) (PE ) was employed as compatibilizer. SEM micrographs but also DSC studies show that MB forms immiscible blend with PE. The dispersed phase of molten MB acts as nucleating agent of PE enhancing the crystallization rate of PE, and also the solidified PE acts as nucleating agent by fastening the crystallization of MB. The values of half-time of crystallization (t 1/2) and the Z c parameter from Avrami's method showed that for a fixed cooling rate, the crystallization rate decreased with the incorporation of hemp fibres and with the addition of the compatibilizer, m{PE^{∗}} PE , showing the retarding effect of both components. Avrami's model was found to provide a fairly satisfactory description of the crystallization kinetics of the studied blends and composites. These results are further supported by the effective activation energy calculations obtained by applying the iso-conversional method of Friedman. CTT diagrams of studied materials were constructed, and they also reflected the effects of each component on the other one but also of hemp fibres and the compatibilizer.