Raw Ramie Research Articles

Biodegumming of ramie fiber with pectinases enhanced by oxygen plasma

A novel biodegumming process with pectinases for ramie fiber was developed in combination with oxygen plasma, in order to improve the efficiency of enzymes in impurity degradation. The results show that a notable positive influence of oxygen plasma on the biodegumming of ramie was achieved, in comparison with a conventional biodegumming process. The fabric weight loss, capillary rise height and whiteness of ramie fabric were evidently improved by employing the oxygen plasma-aided biodegumming process with a half dosage of enzymes, in comparison with a conventional experiment at different temperatures, solution pH values and treatment times. An optimized plasma-aided biodegumming process for raw ramie fabric was recommended with a temperature of 75 °C, a pH value of 8.0 in subjected solution for 60.0 min. Moreover, the role of oxygen plasma on ramie biodegumming was further confirmed by static water contact angle measurement and scanning electron microscopy (SEM) analysis.

Interfacial crystallization enhanced interfacial interaction of Poly (butylene succinate)/ramie fiber biocomposites using dopamine as a modifier

Abstract In this work, dopamine was introduced as a modifier for the surface treatment of ramie fiber. The interfacial crystallization of Poly (butylene succinate) (PBS) on the surface of treated fiber was investigated using polarized light microscope (PLM). It was found that raw ramie fiber has almost no nucleation ability on the crystallization of PBS. However, a beautiful transcrystalline (TC) structure could be successfully induced at the surface of treated fiber, which indicates a significantly improved nucleation ability of dopamine on PBS crystallization. Even more importantly, it was found that the interfacial shear strength between PBS and the treated fiber was very much improved due to the formation of transcrystalline structure. In order to further investigate the role of dopamine on interfacial enhancement, PBS/treated ramie fiber (10 wt%) composites were prepared by compression molding under the same condition with PLM. The tensile test showed that the tensile strength of composites with TC structure was increased by 30% when crystallized for 4 min than that of composites with an amorphous layer when crystallized for 0 min. This result suggested again that the interfacial enhancement was indeed due to the interfacial crystallization. Our work demonstrates that dopamine could be a green and novel surface modifier for natural fiber, and control of interfacial crystallization could be an efficient way for the interfacial enhancement between matrix and fillers.

The effect of new continuous harvest technology of ramie (Boehmeria nivea L. Gaud.) on fiber yield and quality

We investigated a new ramie (Boehmeria nivea L.) harvest mode, which can resolve the bottleneck problems hindering the development of the ramie cultivation industry. In an experiment using cultivar ‘Huazhu 4’, we designed five ramie harvest modes with the conventional harvest mode as the control group. The range of ramie production was 2214.67–2533.67kg/ha, which was lower than the 2724.33kg/ha for conventional harvest (average reduction of 10%). The gel content of all treatments was higher than in the control. The range of average fiber diameter was 15.95±0.28μm to 17.02±0.39μm, fiber diameter in Mode C was optimal. For each harvest mode, the fiber breaking strength was greatest in the first ramie harvested. With the postponing of harvest time, fiber average breaking elongation rate were lower than control except for Modes B and D. In the first harvest (except for Mode D), fiber crystallinity for each mode was significantly different to the control, but not when harvested later. Generally, the average gel content of raw ramie, fiber breaking strength and fiber crystallinity was not significantly different to the control. Continuous harvesting mode was feasible for ramie production.

A rapid process of ramie bio-degumming by Pectobacterium sp. CXJZU-120

Factory tests for rapid process of ramie bio-degumming by Pectobacterium sp. CXJZU-120 were conducted and evaluated comparing the processes of traditional chemical degumming and bio-chemical degumming. Results revealed that over 90% of the gum in raw ramie could be removed only with Pectobacterium sp. CXJZU-120 in 6 h. The rapid process was not only suitable for the extraction of ramie fibers from different grades of raw material and retaining the inherent morphological structures and textile properties, but also could reduce the production cost up to 20.5%, raise resource utilization by more than 50% and reduce pollution charge by more than 80% compared with the traditional chemical degumming. It is a breakthrough in the degumming of ramie and has great application potential in the extraction of herbaceous fiber materials.

The Application of Peracetic Acid and Sodium Percarbonate in Green Production Processing of Ramie

The drawbacks of traditional chemical degumming for raw ramie are long process line, huge energy consumption, with large environment pollution, and low efficiency. Therefore, an attempt has been made to carry out degumming of ramie with an eco-friendly chemical namely, peracetic acid and sodium percarbonate in this communication. Compared with the traditional chemical degumming process, the oxidation degumming process with the characteristics of environment-friendly production technology is short process, less pollution, low energy consumption and high production efficiency and so on. Meanwhile, the hydrolysis products of peracetic acid and sodium percarbonate do a little harm to the environment. Tenacity, fineness, and breaking elongation of degummed samples were determined by standard methods. The results were confirmed through COD, pH, colority, SEM, tensile properties etc. The performance of peracetic acid degumming and sodium percarbonate degumming were also compared with conventional chemical degummed fiber. In addition, the COD, pH value, colority of degumming solution is greatly reduced using oxidation degumming process, environmental pollution and sewage treatment costs are significantly reduced.

Effects of a pretreatment with N‐methylmorpholine‐N‐oxide on the structures and properties of ramie

AbstractTo improve the dyeing properties of ramie, the ecofriendly organic solvent N‐methylmorpholine‐N‐oxide (NMMO) was used to substitute sodium hydroxide as a ramie‐fiber swelling solvent. Through padding and baking pretreatment, ramie fabric was modified by an NMMO aqueous solution. Ultraviolet–visible spectrophotometry, Fourier transform infrared spectroscopy, X‐ray diffraction, and differential scanning calorimetry were used to investigate the effects of NMMO pretreatment on the structure of the ramie, whereas the color strength (K/S, where K is the light absorption coefficient and S is the scattering coefficient), adsorption isotherm, and dye uptake rate curve were measured to investigate the effects of NMMO pretreatment on the dyeing properties of the ramie. The results show that the ramie fiber experienced a limited and irreversible swelling because of the partial breakage of interhydrogen and intrahydrogen bonds of cellulose molecules in the amorphous area, but the crystal and chemical structure of the ramie fiber did not change obviously under the experimental conditions. The K/S value of the NMMO‐modified ramie fabrics dyed with reactive dyes increased by about 100%, and the dye uptake increased by 27.88% compared to that of the raw sample, whereas the standard affinity and diffusion coefficient value of the reactive dyes on the NMMO‐modified ramie fabric were higher than those of the raw ramie fabric. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010

Grafting from ramie fiber with poly(MMA) or poly(MA) via reversible addition-fragmentation chain transfer polymerization

Reversible addition-fragmentation chain transfer (RAFT) polymerization was utilized to control the grafting of methyl methacrylate (MMA) and methyl acrylate (MA) from natural ramie fibers substrate. The hydroxyl groups of ramie fibers were first converted to 2-dithiobenzoyl isobutyrate as a RAFT chain transfer agent (CTA), which was further grafted with MMA or MA mediated by the RAFT polymerization in a presence of 2-(ethoxycarbonyl)prop-2-yl dithiobenzoate as a free chain transfer agent. Hydrophobic poly(MMA) or poly(MA) modified ramie fibers with contact angles greater than 130° were obtained. The modified ramie fibers were analyzed by gravimetry, Fourier transform infrared spectroscopy, scanning electron microscopy, differential scanning calorimetry, thermogravimetry and contact angle measurements. The results indicate that the polymer chains had indeed been grafted from the surface of the ramie fibers with an average 33% of the hydroxyl groups in the raw ramie fiber substituted by 2-bromoisobutyryl bromide and an average grafting ratio of 25% poly(MMA) or poly(MA) related to ramie fiber. The homopolymers formed in the copolymerization were also analyzed to estimate molecular weights and polydispersity indices of grafting chains from the surface of ramie fibers by size exclusion chromatography, which showed narrow polydispersity with the PDIs to be <1.32. This study provides a novel and feasible approach to the preparation of functional composite materials for utilizing the abundant natural ramie fiber cellulose resource.

Study on the performance of ramie fiber modified with ethylenediamine

The chelate molecule, ethylenediamine, was incorporated onto the surface of ramie fiber via sequential reactions of the hydroxyl groups on ramie fiber with epichlorohydrin followed by the chelating agent. The performance of the modified material (CelNH) was characterized by Fourier transform infrared spectroscopy (FI-IR), X-ray diffraction (XRD), scanning electron micrographs (SEM), thermogravimetry analysis (TGA), UV–Vis, and elemental analysis. Results show that the excellent characteristics of the raw fiber were still remained after modification although the crystallinity of the modified fiber decreased. The modification parameters were optimized as the concentration of ethylenediamine of 0.75 mol/l, the temperature of 50 °C, and the reaction time of 5 h. Meanwhile, the dye of C.I. reactive red 2 was used to study the dyeability of the raw and the modified fibers. The color strength and the dye uptake of the modified fiber increased obviously with an increase in the nitrogen contents in CelNH. The color strength and the dye uptake of the modified fiber can be controlled by changing the extent of surface modification of raw ramie fiber.

Radial distribution function analysis study on alkali and heat‐treated ramie fiber

AbstractThe radial distribution function (RDF) analysis of wide‐angle X‐ray diffraction by ramie fibers in untreated condition and after treatment with alkali of mercerizing strength or heat have been carried out. Interatomic distances, coordination numbers, mean square displacements, and coupling constants for different atom pairs have been calculated. The results have been interpreted in terms of a difference in both the conformation and packing of molecular chains in raw and alkali‐treated ramie. In general, the coupling constant values have been found to be more in alkali‐treated ramie, indicating relatively weak bond strength. Heat‐treated ramie shows a marginal decrease in coupling constant values. © 1994 John Wiley &amp; Sons, Inc.

Ramie: Patterns of World Production and Trade

Ramie has been grown in the Far East for many centuries and its fibre used for making cloth even before the introduction of cotton. Despite the fibre's use for a wide variety of products, it was little known in North American markets or widely traded until the 1980s. This paper includes a review of historical and current literature on ramie production and trade, as well as analyses of U.S. Department of Commerce and United Nations data. Trade patterns from 1930 to 1979 were reconstructed from historical documents. In the most recent period, from 1980 to 1986, three states of ramie trade were examined: (i) raw ramie, (ii) processed ramie, and (iii) apparel products. Worldwide trading patterns according to stage of processing are described and analysed. Ramie products exported to the U.S. market were examined on the category level to assess changes in trading patterns. Major shippers of particular types of ramie and ramie-blend garments were determined. The relationship between ramie trade and the provision...

醗酵による繊維の精練

We investigated the microbiological degumming of ramie-fiber by using a strain of Aspergillus nicer isolated from raw ramie. The submerged culture-fluid was used for that purpose so that the retting-time may be saved and the back spores may not damage the fiber. In the shaking culture, production of depectinizing enzyme is accelerated by use of alkali scouring waste liquor of ramie as culture medium. The addition of stillage as nutrient is highly effective. The less the amount of C source was added to alkali scouring waste liquor (the basal medium), the more the amount of protopectinase was produced, so far as the develop-ment of the mold and the production of oxalic acid were concerened. The highest activity of protopectinase out of influence of oxalic acid was obtained on the following cultural conditions: media: A. S. W. L, 100+glucose 2+peptone 1; initial pH: 5.2_??_7.6; temp.: 29_??_35°C. Though conditions of retting are not yet fully studied, we can expect cooperative effect of the enzyme and oxalate produced in the culture, so that the fiber may be degummed in short-er time than a day at the temperature as low a_??_30_??_40°C.