Comparative Study of Mechanical Properties and Thermal Stability on Banyan/Ramie Fiber-Reinforced Hybrid Polymer Composite

The usage of natural fibers has increased recently. They are used to replace synthetic fiber products in aircraft and automobile industries. In this study, natural fibers of bidirectional banyan mat and ramie fabrics are used for reinforcement, and the matrix is an epoxy resin to fabricate composite laminates by traditional hand layup technique at atmospheric temperature mode. Five different sequences of reinforcements are as follows to quantify the effect of thermal stability and mechanical behavior of silane-treated and untreated hybrid composites. The results revealed that silane-treated fabric composite laminates were given enhanced mechanical properties of 7% tensile, 11% flexural, and 9% impact strength compared with untreated fabric composite, and at the same time when the increasing of ramie fabric was given the positive influence of 41% improved tensile strength of 40.7 MPa, 49% improved in flexural strength of 38.9 MPa and negative influence in 57% lower impact strength in sample E and positive value in sample A 21.12 J impact energy absorbed in the hybrid composite. Thermogravimetric analysis (TGA) revealed the thermal stability of the hybrid composite. In sample A, the thermal stability is more than in other samples, and 410°C is required to reduce the mass loss of 25%. The working mass condition of the hybrid composite is up to 3.25 g after it moves to degrade.

Identification of proteins associated with bast fiber growth of ramie by differential proteomic analysis

Background Ramie is an important fiber-producing crop in China, and its fibers are widely used as textile materials. Fibers contain specialized secondary cellular walls that are mainly composed of cellulose, hemicelluloses, and lignin. Understanding the mechanism underlying the secondary wall biosynthesis of fibers will benefit the improvement of fiber yield and quality in ramie. Results Here, we performed a proteomic analysis of the bark from the top and middle parts of the stem, where fiber growth is at different stages. We identified 6971 non-redundant proteins from bast bark. Proteomic comparison revealed 983 proteins with differential expression between the two bark types. Of these 983 proteins, 46 were identified as the homolog of known secondary wall biosynthetic proteins of Arabidopsis, indicating that they were potentially associated with fiber growth. Then, we proposed a molecular model for the secondary wall biosynthesis of ramie fiber. Furthermore, interaction analysis of 46 candidate proteins revealed two interacting networks that consisted of eight cellulose biosynthetic enzymes and seven lignin biosynthetic proteins, respectively. Conclusion This study sheds light on the proteomic basis underlying bast fiber growth in ramie, and the identification of many candidates associated with fiber growth provides important basis for understanding the fiber growth in this crop.

Ramie fiber reinforced composites with flame retardant structure design: flammability, smoke suppression, and mechanical properties

In this work, the structure of composite was designed as Core Stack and Surface Stack, which was treated with the expandable graphite (EG) and metal oxides such as iron oxide (IO), hydroxyapatite (HA), and aluminum tri-hydroxide (ATH). The mechanical performance of composites was characterized via flexural performance and interlaminar shear strength analysis. The flame retardance and smoke suppression of composite was explored in detail by LOI, UL-94, and cone calorimeter test. The findings presented that flexural properties of composites were observed to decrease due to delamination of surface stack, whilst no significant effect on interlaminar shear strength. In comparison with control composite, the loading of metal oxide into composite Surface Stack led to the reduction of peak heat release rate, total heat release, and fire growth index effectively. Moreover, the remarkable decrease in total smoke production could be observed due to the addition of iron oxide and the flame retardant mechanism was discussed. This study was the preliminary exploration of composite with flame retardant design which could be potential solution to improve flame retardancy and smoke suppression of composite with better mechanical structure preservation.

Mechanical and Dynamic Mechanical Properties of the Amino Silicone Oil Emulsion Modified Ramie Fiber Reinforced Composites

The mechanical and dynamic mechanical properties, interface adhesion and microstructures of the amino silicone oil emulsion (ASO) modified short ramie fiber reinforced polypropylene composites (RFPCs) with different fiber fractions were investigated. The RFPCs were made through a combined process of extrusion and injection molding. Mechanical property tests of the RFPCs revealed enhancements in tensile and flexural strengths with increase of the fiber fraction due to the high stiffness of the fiber filler and a better interfacial bonding from ASO treatment. The dynamic mechanical analysis (DMA) results indicated that fiber incorporation plays an important role in DMA parameters (storage modulus, loss modulus, and damping ratio) at Tg by forming an improved interfacial adhesion and providing more effective stress transfer rate and energy dissipation between matrix and fiber. The phase behavior analysis suggests all the RFPCs are a kind of heterogeneity system based on the Cole-Cole plot analysis.

Enhancing Thermal and Mechanical Properties of Ramie Fiber via Impregnation by Lignin-Based Polyurethane Resin

In this study, lignin isolated and fractionated from black liquor was used as a pre-polymer to prepare bio-polyurethane (Bio-PU) resin, and the resin was impregnated into ramie fiber (Boehmeria nivea (L.) Gaudich) to improve its thermal and mechanical properties. The isolated lignin was fractionated by one-step fractionation using two different solvents, i.e., methanol (MeOH) and acetone (Ac). Each fractionated lignin was dissolved in NaOH and then reacted with a polymeric 4,4-methane diphenyl diisocyanate (pMDI) polymer at an NCO/OH mole ratio of 0.3. The resulting Bio-PU was then used in the impregnation of ramie fiber. The characterization of lignin, Bio-PU, and ramie fiber was carried out using several techniques, i.e., Fourier-transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), pyrolysis-gas-chromatography-mass-spectroscopy (Py-GCMS), Micro Confocal Raman spectroscopy, and an evaluation of fiber mechanical properties (modulus of elasticity and tensile strength). Impregnation of Bio-PU into ramie fiber resulted in weight gain ranging from 6% to 15%, and the values increased when extending the impregnation time. The reaction between the NCO group on Bio-PU and the OH group on ramie fiber forms a C=O group of urethane as confirmed by FTIR and Micro Confocal Raman spectroscopies at a wavenumber of 1600 cm−1. Based on the TGA analysis, ramie fiber with lignin-based Bio-PU had better thermal properties than ramie fiber before impregnation with a greater weight residue of 21.7%. The mechanical properties of ramie fiber also increased after impregnation with lignin-based Bio-PU, resulting in a modulus of elasticity of 31 GPa for ramie-L-isolated and a tensile strength of 577 MPa for ramie-L-Ac. The enhanced thermal and mechanical properties of impregnated ramie fiber with lignin-based Bio-PU resins could increase the added value of ramie fiber and enhance its more comprehensive industrial application as a functional material.

Weaving and mechanical properties test of polylactic acid/ramie composite fabric

In view of the weak mechanical properties of polylactic acid fiber, the excellent mechanical properties of ramie fiber are selected to enhance the performance of polylactic acid fiber, thereby forming a composite fabric, and weaving plain weave fabric, twill weave fabric, satin weave fabric and square plain fabric by weaving method., Twill change fabric and satin change fabric six kinds of fabrics. Electronic thickness meter, electronic strength meter, and electronic bursting tester were used to test the thickness, tensile fracture and burst performance of 6 kinds of fabrics, and the reasons for the differences between the fabrics were discussed. The research results show that the mechanical properties of composite fabrics are better than those of pure polylactic acid fabrics. In addition, in terms of tensile fracture performance, the satin weave fabric is the strongest, and the satin weave is the strongest in burst performance. In terms of fabric thickness, the lowest thickness value is plain weave, but the thickness value, tensile breaking and bursting properties of square flat fabrics are ranked second, so the overall performance is always the strongest.

Studi Konsentrasi Larutan KOH dan Arah Orientasi Serat Rami terhadap Kekuatan Impak Komposit dengan Matrik Polyester

The development of increasingly advanced technology, especially in the health sector, can lead to an increase in the need for composite materials used. This study aims to describe the results of the concentration of KOH solution and the orientation of the ramie fiber on the impact strength of composites with a polyester matrix. This research is an experimental study with the manipulation variables are the concentration of the KOH solution and the orientation of the fiber direction by determining the value of the impact strength as the dependent variable of ramie fiber as a control variable of this study. This study obtained the optimum impact test result of 0.0711 J/mm2 with 5% KOH solution concentration and located at 0o/45o/90o fiber direction orientation. While the results of the lowest impact test resulted in a value of 0.0101 J/mm2 without soaking the KOH solution and located at 90o/0o/90o fiber direction orientation.

Phosphoproteome analysis reveals an extensive phosphorylation of proteins associated with bast fiber growth in ramie

Background Phosphorylation modification, one of the most common post-translational modifications of proteins, widely participates in the regulation of plant growth and development. Fibers extracted from the stem bark of ramie are important natural textile fibers; however, the role of phosphorylation modification in the growth of ramie fibers is largely unknown. Results Here, we report a phosphoproteome analysis for the barks from the top and middle section of ramie stems, in which the fiber grows at different stages. A total of 10,320 phosphorylation sites from 9,170 unique phosphopeptides that were assigned to 3,506 proteins was identified, and 458 differentially phosphorylated sites from 323 proteins were detected in the fiber developmental barks. Twelve differentially phosphorylated proteins were the homologs of Arabidopsis fiber growth-related proteins. We further focused on the function of the differentially phosphorylated KNOX protein whole_GLEAN_10029667, and found that this protein dramatically repressed the fiber formation in Arabidopsis. Additionally, using a yeast two-hybridization assay, we identified a kinase and a phosphatase that interact with whole_GLEAN_10029667, indicating that they potentially target this KNOX protein to regulate its phosphorylation level. Conclusion The finding of this study provided insights into the involvement of phosphorylation modification in ramie fiber growth, and our functional characterization of whole_GLEAN_10029667 provide the first evidence to indicate the involvement of phosphorylation modification in the regulation of KNOX protein function in plants.