The crystallization kinetics of Poly(lactic acid) / talc composites were determined over a range of 0 wt.% to 15 wt.% of talc. Talc was found to change the crystallization kinetics. The presence of talc increases the crystallization rate and this increase is related to talc concentration and to crystallization temperature. In order to understand the effect of talc and PLA crystallinity on mechanical properties, dynamic mechanical thermal analyses were performed on Poly(lactic acid) / talc composites before and after an annealing process. It was demonstrated that the presence of crystals improves thermo-mechanical properties but in order to achieve good results at high temperatures the reinforcing effect of a filler such as talc is necessar
In a singular period, such as during a pandemic, the use of personal protective masks can become mandatory for all citizens in many places worldwide. The most used device is the disposable mask that, inevitably, generates a substantial waste flow to send to incineration or landfill. The article examines the most diffused type of disposable face mask and identifies the characteristic of the constituent materials through morphological, chemical, physical, and thermal analyses. Based on these investigations, a mechanical recycling protocol with different approaches is proposed. Advantages and disadvantages of the different recycling solutions are discussed with considerations on necessary separation processes and other treatments. The four solutions investigated lead to a recycling index from 78 to 91% of the starting disposable mask weight. The rheological, mechanical, and thermo-mechanical properties of the final materials obtained from the different recycling approaches are compared with each other and with solutions present on the market resulting in materials potentially industrially exploitable.
The paper describes the production and the mechanical characteristics of composites made completely of renewable raw materials. Several wastes or by-products from agro-industrial production namely hemp hurd, alfalfa, and grape stem were analyzed with respect to their thermal stability, morphological, and chemical composition in an attempt to validate their use in composites. Such natural particle fillers were used in the range of 10–50 wt% in combination with poly(lactic acid) by melt blending to obtain fully bio-based composites. These fillers were responsible for a noteworthy increase in the storage modulus. Furthermore, two micromechanical models (Voigt and Halpin–Tsai) were used to mathematically fitted the experimental data, and then the unknown moduli were extrapolated and compared with other natural fillers. Finally, the flexural strength of the bio-composites and the adhesion evaluation by exploiting Pukanszky’s model were carried out. As a result, the hemp hurd in the form of chips was the best investigated filler, which showed the highest calculated modulus of 10.5 GPa (Voigt) and the best filler–matrix interaction with “B” (Pukanszky’s coefficient) of 2.10. This information can be useful when comparison and selection of a suitable filler among the natural fillers are required.
28 July 2013 in Journal of Polymers and the Environment