Interfacial modified unidirectional wheat straw/polylactic acid composites

Abstract

Among the agricultural crops, wheat is one of the most important and broadly planted food crops. However, abundant wheat straw resources were used to incinerate, which was a great waste of fiber resources, and meanwhile caused great pollution to the ecological environment. In this work, a simple hot compress method that used intact wheat straw with different volume fractions (20% and 30%) as a filler to reinforce the polylactic acid resin was explored to prepare a biodegradable composite by thermal compression method. Initially, the compressed wheat straw exhibited excellent tensile strength (96.86 MPa), even higher than intact wheat straw (92.18 MPa). The surface modification treatment was carried out with 2% and 4% concentrations of sodium hydroxide (NaOH). Then the tensile and bending strength of the modified wheat straw/polylactic acid composites were 32.41 MPa and 78.52 MPa, which were 22.16% and 22.44% higher than those of the untreated composites. The scanning electron microscopy images of the surface of modified wheat straw and fractured composite cross section revealed significantly rougher surface morphology and stronger interfacial bonding with the matrix. This work demonstrated the feasibility and good mechanical property of the composites reinforced with intact wheat straw by simple hot compression method, which provided a possible strategy to utilize the straw materials for multiple applications.

Comparison of Properties of Poly(Lactic Acid) Composites Prepared from Different Components of Corn Straw Fiber

“…As shown in Figure 2 c, when the diameter of the SCF reached more than 20–40 mesh, increases in the bending strength of all the CSFS/PLA composite samples were not significant and reached the same level of approximately 87 MPa. This is because the large dimensions of CSF are unevenly dispersed in the PLA layer and PLA cannot cover the fibers well, resulting in slippage between the CSF and the PLA matrix [ 35 ]. The CSF with large particle sizes is easy to form defects, such as voids in the interface layer of the composite material.…”

Conversion of Waste Agricultural Biomass from Straw into Useful Bioproducts—Wheat Fibers and Biofuels

“…Alternatively, it can serve as a raw material for nanocellulose fabrication, which can then be utilized as a wastewater cleaner [28][29][30]. Wheat cellulose fibers are already used in the composite and paper industry [31][32][33][34][35][36][37] and, upon modification, can be used for very different purposes [38][39][40][41][42][43][44].…”

“…Wheat straw infused with animal glue as reinforcement in composite materials [38] Wheat fibers isolated by mechanical process and microbial retting (fiber length is up to 4 mm) [45] Wheat straw as reinforcement in composite materials (chopped to the size 18-20 cm, 5 to 15 mm, and 2.5 cm; milled to the particle size up to 1 mm) [31][32][33]35] Wheat straw fiber-based hand sheets (unbleached wheat straw fibers, fiber length < 0.58 mm) [39,43] Wheat straw fibers as building material (milled and sieved straw, particle size 0.3 mm, and chopped straw up to 32 mm in length) [23,24] Milled wheat straw as reinforcement for biocomposites.…”

Çelti̇k Li̇fi̇ Takvi̇yeli̇ Bi̇yo Kompozi̇t Malzemeni̇n Mekani̇k Özelli̇kleri̇ni̇n İncelenmesi̇

“…Bu biyo-kompozitler, cam yünü veya karbon bazlı diğer kompozitlere bir alternatiftir. Literatürde, bitkisel atık liflerine uygulanan ön işlem olarak; pektinaz enzimi ile keten liflerinin ıslatılması [16], keten liflerinin Bioprep 3000 ve etilen diamin tetraasetik asit (EDTA) alkali pektat liyaz (PL) [18], Bioprep 3000L ve Texayzm BFE kullanılarak enzimatik işlemler [17], 2-4-6 mm uzunluğunda kesilmiş pirinç samanlarını, 150°C'de %1-5 NaOH içinde 2 saat süre ile muamele [33], oksalik asit ve sıcak su, NaOH ile işlenmiş pirinç sapları , kompost uygulamalarında pektinaz ve kalsiyum mekanizmalarının gözden geçirilmesi, keten türleri ve kullanılmış pektinaz çeşitlerinin toplanma çalışmaları [19], %1-3-5 alkali solüsyonla işlenmiş buğday samanları ile çalışmalar yapılmıştır [29]. Zhao ve ark.…”

“…Bu işlemin bir sonucu olarak, PLA matrisi ile Çeltik lifindeki selüloz arasında iyi bir mekanik bağlanma meydana gelir. Ayrıca yapışma özellikleri açısından PLA, daha az polar gruba sahip olmasına rağmen, selüloz molekülleri ile hidrojen bağları oluşturmak için reaksiyon bölgelerinin sayısı artar[29]. Tek katmanlı pirinç lifi/PLA biyokompozit malzeme üretiminde kullanılan liflere alkali ve ısıl ön işlem uygulanmıştır.…”