Biocomposites reinforced with natural fibers: 2000–2010

Recently, there has been a rapid growth in research and innovation in the natural fibre composite (NFC) area. Interest is warranted due to the advantages of these materials compared to others, such as synthetic fibre composites, including low environmental impact and low cost and support their potential across a wide range of applications. Much effort has gone into increasing their mechanical performance to extend the capabilities and applications of this group of materials. This review aims to provide an overview of the factors that affect the mechanical performance of NFCs and details achievements made with them.

A review of recent developments in natural fibre composites and their mechanical performance

Physical and mechanical properties of PLA, and their functions in widespread applications - A comprehensive review.

Poly(lactic acid) (PLA), so far, is the most extensively researched and utilized biodegradable aliphatic polyester in human history. Due to its merits, PLA is a leading biomaterial for numerous applications in medicine as well as in industry replacing conventional petrochemical-based polymers. The main purpose of this review is to elaborate the mechanical and physical properties that affect its stability, processability, degradation, PLA-other polymers immiscibility, aging and recyclability, and therefore its potential suitability to fulfill specific application requirements. This review also summarizes variations in these properties during PLA processing (i.e. thermal degradation and recyclability), biodegradation, packaging and sterilization, and aging (i.e. weathering and hygrothermal). In addition, we discuss up-to-date strategies for PLA properties improvements including components and plasticizer blending, nucleation agent addition, and PLA modifications and nanoformulations. Incorporating better understanding of the role of these properties with available improvement strategies is the key for successful utilization of PLA and its copolymers/composites/blends to maximize their fit with worldwide application needs.

Physical and mechanical properties of PLA, and their functions in widespread applications — A comprehensive review

https://hal.archives-ouvertes.fr/hal-02119698/document

Mechanical properties of components fabricated with open-source 3-D printers under realistic environmental conditions

https://hal.archives-ouvertes.fr/hal-00671654/document

Mechanical performance of biocomposites based on PLA and PHBV reinforced with natural fibres – A comparative study to PP

PLA biocomposites with abaca and man-made cellulose fibres were processed by using combined moulding technology: two-step extrusion coating process and consecutively injection moulding. By adding 30 wt% of man-made cellulose, the Charpy impact strength at ambient temperature increased by factor 3.60, compared to unreinforced PLA. Tensile strength rose by factor 1.45 and stiffness by approx. 1.75. Reinforcing with abaca fibres (30 wt%) enhanced both E-Modulus and tensile strength by factor 2.40 and 1.20, respectively. The Charpy A-notch impact resistance of PLA/abaca could be improved by factor 2.4. SEM photographs show fibre pull-outs from the polymer matrix. The fibre orientation was analysed via optical microscopy. The after-process fibre length was significantly affected already during compounding process.

Mechanical properties of PLA composites with man-made cellulose and abaca fibres

Polypropylene composites with enzyme modified abaca fibre

In the first part of this study, the improvement of mechanical performance of composites based on polylactide in comparison to petrochemical polypropylene is presented. This approach focuses on understanding the micromechanical aspects of brittle and ductile failure mechanisms of composites with natural fiber abaca, man-made cellulose and glass fiber. The basic principal is hereby the utilization of cellulosic fibers in a biogenic matrix polymer and the comparison to PP-based composites. The findings obtained in the first sections are the main essentials for the second part of this paper: further improvement of crash resistance of PLA composites. The main objective is to improve the mechanical parameters while the primarily targeting is on the impact strength of the brittle polylactide composites. In the course of this thesis, the ultimate proof of the reinforcing effects of cellulosic fibers was provided. Finally, a selective modification of the interphase was accomplished and accordingly, the highest known values of impact strength for PLA composites were achieved.

Improving the mechanical performance of PLA composites with natural, man-made cellulose and glass fibers — a comparison to PP counterparts

The presented contribution deals with the material properties of chain-extended polylactide. In the course of this study, two different functional additives were used, namely an epoxidized and a maleated styrene-acrylic copolymer. Both additives were compounded together with polylactide using a conventional twin-screw extruder, and were then injection moulded to standardized testing specimens. The main focus of the investigation is on structural changes as well as the mechanical performance, e.g. crack propagation and arresting mechanisms that are affected by reactive chain extension. The first section of the experimental part consists of results regarding modifications achieved on the macromolecular level. Based on size exclusion chromatography and DSC-OIT experiments, different structural changes and their influence on the material behaviour are presented. Subsequently, a comprehensive analysis of the quasi-static tests and the impact strength of notched and unnotched specimens was performed, and correlated with the following fatigue experiments. A discussion concerning morphological aspects and finally a correlation to the fracture surface topography after fatigue test completes the experimental part.

/pdf/how-does-a-chain-extended-polylactide-behave-a-comprehensive-abiec28unv.pdf

Adam Jaszkiewicz

Papers

Mechanical performance of biocomposites based on PLA and PHBV reinforced with natural fibres – A comparative study to PP

Mechanical properties of PLA composites with man-made cellulose and abaca fibres

Polypropylene composites with enzyme modified abaca fibre

Improving the mechanical performance of PLA composites with natural, man-made cellulose and glass fibers — a comparison to PP counterparts

How does a chain-extended polylactide behave?: a comprehensive analysis of the material, structural and mechanical properties