Biopolymer‐based composites have attracted the attention of researchers and industries due to their eco‐friendliness and environmental sustainability, as well as their suitability for a number of applications. Biocomposites containing natural fibers and biopolymers would be the ideal choice in the development of biodegradable materials for different applications. Polylactic acid (PLA) is an environmentally interesting biopolymer, which also has exclusive qualities, such as good transparency and processability, glossy appearance, and high rigidity, although it has some shortcomings as well, for example, its brittleness and high rate of crystallization. PLA‐based natural fiber composites are entirely bio‐based materials with promising biodegradability and mechanical properties. Several research studies have been carried out on PLA and its composites to explore their potential to substitute petroleum‐based products, but until now there is no comprehensive review with up‐to‐date research data available in the literature. The aim of this review is to highlight the trends in the research and development of PLA and PLA‐based natural fiber composites over the past few years. This review article covers current research efforts on the synthesis and biodegradation of PLA, its properties, trends, challenges and prospects in the field of PLA and its composites. PLA‐based composites are moderately abundant; and further research and development is needed for cost reduction and broader utilization. POLYM. COMPOS., 40:446–463, 2019. © 2018 Society of Plastics Engineers

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Natural fiber‐based polymer composites have been widely studied to substitute synthetic materials. In this research, pineapple leaf fibers (PALF) and coir fibers (CF) were loaded into a polylactic acid (PLA) matrix to develop composite materials with improved mechanical and thermal properties, which could be potentially applied as biodegradable food packaging. Biocomposites with different fiber ratios were manufactured using an internal mixer plasticizer and a hot press machine. Mechanical and thermal analyses of the obtained composites were carried out and the results were compared with those of pure PLA. Scanning electron microscopy (SEM) was used to observe the microstructural failure of the composites. Mechanical tests indicated that all the composites had higher tensile and flexural modulus, compared to those of neat PLA. Also, strength values were increased upon addition of PALF, while impact tests showed enhanced strength results upon addition of CF. SEM findings confirmed the outcomes of the mechanical tests. DMA results confirmed that the storage and loss moduli of the CF/PALF/PLA hybrid composites increased with respect to those of the neat PLA, whereas the tan δ decreased. The coefficient of thermal expansion (CTE) of the PLA composites decreased with the addition of fiber reinforcements. Based on the results achieved in this investigation, the hybrid composite containing CF and PALF in a 1:1 ratio (C1P1) presented the optimum set of mechanical properties and improved thermal stability, which make it suitable for applications such as food packaging and structure components to help reduce the environmental loads. POLYM. COMPOS., 40:2000–2011, 2019. © 2018 Society of Plastics Engineers

The manufacturing of fiberboard from wood fiber with the help of adhesive is highly developed and widely commercialized technique. However, with an increasing concern over health issues and biomass conservation, the fiberboards from agriculture residues with or without using adhesives are under intensive investigation. In last three decades, several researches have been done various methods and technique dealing the development of binderless fiber boards such as wet process and dry process. This review article also covered pretreatments of fiber which helps to find out optimum criteria for fabrication of fibreboards. Fibre sizes in fibreboard were studied and found that the dimensions of fibres effect the physical, mechanical and thermal properties. The pressing time and temperature influence the internal bonding of binderless fibreboards. The mechanical and thermal properties of binderless fibresboard were discussed on various pressing time and temperature and compared with different type fibreboards. Effect of hygrothermal properties on the physical, mechanical and thermal behavior of binderless were also discussed. This review summarized various aspects of self-bonding mechanism in binderless fibresboard with a focus on agriculture residues based raw materials. Various aspects of binderless fiberboard manufacturing such as raw material suitability, effects of pretreatments and manufacturing process on physical, mechanical and thermal properties are discussed. The chemical changes in fiber during pretreatments and hot pressing is also discussed in detail. These binderless fiberboard showed the suitability in use for indoor applications due to its non-toxic characteristics.

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