Interfacial modified unidirectional wheat straw/polylactic acid composites

2020 ◽  
pp. 152808372091817
Author(s):  
Wuzhou Li ◽  
Liangang Zheng ◽  
Defang Teng ◽  
Dongsheng Ge ◽  
Farial I Farha ◽  
...  

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.

2012 ◽  
Vol 627 ◽  
pp. 715-721
Author(s):  
Li Ying Wu ◽  
Fu Jun Xu ◽  
Peng Wei Zhao ◽  
Yi Ping Qiu

Polylactic Acid (PLA) and raw Wheat Straw (WS) were used to fabricate WS/PLA green composites. By hot-press process, WS/PLA composites with different WS volume fractions (20% and 30%) were obtained. The experimental results showed that when the WS volume fraction was 20%, the composites had a tensile strength of 23.68MPa and modulus of 1.47GPa; bending strength of 64.13MPa and modulus of 1.44GPa. When the WS volume fraction increased to 30%, the tensile strength and modulus enhanced by 45.18% and 35.37% respectively; bending strength and modulus increased by 15.80% and 25.69%. It was indicated that PLA can be successfully reinforced by WS at certain volume fractions.


Polymers ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1124
Author(s):  
Zhifang Liang ◽  
Hongwu Wu ◽  
Ruipu Liu ◽  
Caiquan Wu

Green biodegradable plastics have come into focus as an alternative to restricted plastic products. In this paper, continuous long sisal fiber (SF)/polylactic acid (PLA) premixes were prepared by an extrusion-rolling blending process, and then unidirectional continuous long sisal fiber-reinforced PLA composites (LSFCs) were prepared by compression molding to explore the effect of long fiber on the mechanical properties of sisal fiber-reinforced composites. As a comparison, random short sisal fiber-reinforced PLA composites (SSFCs) were prepared by open milling and molding. The experimental results show that continuous long sisal fiber/PLA premixes could be successfully obtained from this pre-blending process. It was found that the presence of long sisal fibers could greatly improve the tensile strength of LSFC material along the fiber extension direction and slightly increase its tensile elongation. Continuous long fibers in LSFCs could greatly participate in supporting the load applied to the composite material. However, when comparing the mechanical properties of the two composite materials, the poor compatibility between the fiber and the matrix made fiber’s reinforcement effect not well reflected in SSFCs. Similarly, the flexural performance and impact performance of LSFCs had been improved considerably versus SSFCs.


BioResources ◽  
2020 ◽  
Vol 15 (4) ◽  
pp. 7954-7964
Author(s):  
Diego Gomez-Maldonado ◽  
Maria Soledad Peresin ◽  
Christina Verdi ◽  
Guillermo Velarde ◽  
Daniel Saloni

As the additive manufacturing process gains worldwide importance, the need for bio-based materials, especially for in-home polymeric use, also increases. This work aims to develop a composite of polylactic acid (PLA) and nanofibrillated cellulose (NFC) as a sustainable approach to reinforce the currently commercially available PLA. The studied materials were composites with 5 and 10% NFC that were blended and extruded. Mechanical, structural, and thermal characterization was made before its use for 3D printing. It was found that the inclusion of 10% NFC increased the modulus of elasticity in the filaments from 2.92 to 3.36 GPa. However, a small decrease in tensile strength was observed from 55.7 to 50.8 MPa, which was possibly due to the formation of NFC aggregates in the matrix. This work shows the potential of using PLA mixed with NFC for additive manufacturing.


Polymers ◽  
2018 ◽  
Vol 10 (8) ◽  
pp. 896 ◽  
Author(s):  
Qiqi Fan ◽  
Guangping Han ◽  
Wanli Cheng ◽  
Huafeng Tian ◽  
Dong Wang ◽  
...  

In this work, an easy way to prepare the polylactic acid (PLA)/wheat straw fiber (WSF) composite was proposed. The method involved uses either the dopamine-treated WSF or the two-step montmorillonite (MMT)-modified WSF as the filler material. In order to achieve the dispersibility and exfoliation of MMT, it was modified by 12-aminododecanoic acid using a two-step route. X-ray diffraction (XRD) and scanning electron microscopy (SEM) were performed to characterize the modified MMT and the coated WSF. As for the properties of PLA/WSF composites, some thermal (using Fourier transform infrared spectroscopy (FT-IR) and thermogravimetric analysis) and mechanical properties (flexural, tensile, and impact) were analyzed. The results showed that the dopamine was successfully coated onto the WSF. Furthermore, Na-MMT was successfully transformed to organo-montmorillonite (OMMT) and formed an exfoliated structure. In addition, a better dispersion of MMT was obtained using the two-step treatment. The interlayer spacing of modified MMT was 4.06 nm, which was 123% higher than that of the unmodified MMT. Additionally, FT-IR analysis suggested that OMMT diffused into the PLA matrix. The thermogravimetric analysis (TGA) showed that a higher thermal stability of PLA/WSF composites was obtained for the modified MMT and dopamine. The results also showed that both the dopamine treated WSF and the two-step-treated MMT exhibited a positive influence on the mechanical properties of PLA/WSF composites, especially on the tensile strength, which increased by 367% compared to the unmodified precursors. This route offers researchers a potential scheme to improve the thermal and mechanical properties of PLA/WSF composites in a low-cost way.


2017 ◽  
Vol 17 (1) ◽  
pp. 27-30
Author(s):  
R. Dańko

Abstract The results of investigations of the influence of the matrix grain sizes on properties of cores made by the blowing method are presented in the hereby paper. Five kinds of matrices, differing in grain size compositions, determined by the laser diffraction method in the Analysette 22NanoTec device, were applied in investigations. Individual kinds of matrices were used for making core sands in the Cordis technology. From these sands the shaped elements, for determining the apparent density of compacted sands and their bending strength, were made by the blowing method. The shaped elements (cores) were made at shooting pressures being 3, 4 and 5 atn. The bending strength of samples were determined directly after their preparation and after the storing time of 1 hour.


2018 ◽  
Vol 192 ◽  
pp. 03002
Author(s):  
Jedsada Chaishome ◽  
Suriyan Supapvanich

This paper reports on a study of the compression moulding and the vacuum forming of unidirectional pineapple leaf fibres/polylactic acid composites and the influence of process variables on the tensile properties of the material. The characterisation of the micro and meso structures of the pineapple leaf fibres is reported. The effect of consolidation temperature on the fibre thermal stability and the tensile properties of the composites is investigated. The results show that vacuum forming was found to be preferable process with high stiffness modulus and UTS of the composites, compared to compression moulding. The insignificant detrimental effect of 165°C high consolidation temperature was observed. Finally, the fibre thermal degradation seems to dominate the composite tensile performance over its interfacial quality between the fibre and the matrix.


2021 ◽  
Vol 889 ◽  
pp. 44-49
Author(s):  
Yeng Fong Shih ◽  
Zheng Ting Chen ◽  
Wei Lun Lin ◽  
Po Chun Chiu ◽  
Chin Hsien Chiang ◽  
...  

The purpose of this research is to develop a new type of environmentally friendly container which has thermostatic effect and is biodegradable. This study is based on polylactic acid (PLA) and maleic anhydride grafted polybutylene succinate (MAPBS). Subsequently, the diatomite which adsorbed polyethylene glycol (PEG) was added to prepare a thermostatic biodegradable composite. The addition of MAPBS is to improve the compatibility between PLA and diatomite. In addition, the thermostatic effect, tensile strength, thermal deformation temperature and impact strength of the composite were investigated.


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