Xiuliang Hou

Bio-thermoplastics from grafted chicken feathers for potential biomedical applications.

This research demonstrated the feasibility of using bio-thermoplastics developed from chicken feathers grafted with acrylates and methacrylates as scaffolds for tissue engineering. Keratin, the major protein in feathers, is a highly crosslinked biopolymer that has been reported to be biocompatible. However, it is difficult to break the disulfide bonds and make keratin soluble to develop materials for tissue engineering and other medical applications. Previously, keratin extracted from feathers using alkaline hydrolysis has been made into scaffolds but with poor water stability and mechanical properties. In this study, thermoplastic films were compression molded from chicken feathers grafted with 6 different acrylate monomers. The influence of the concentration and structures of grafted monomers on grafting parameters and the tensile strength, water stability and cytocompatibility of grafted feathers compression molded into films were investigated. It was found that the grafted feather films were water stable and had good strength and better supported cell growth than poly(lactic acid) films. Grafted feathers demonstrated the potential to be used for fabrication of biomaterials for various biomedical applications.

Pure keratin membrane and fibers from chicken feather.

In this research, keratin was extracted from the disposable chicken feather using l-cysteine as reducing agent. Then, it was re-dissolved in the sodium carbonate-sodium bicarbonate buffer, and the pure keratin membrane and fiber were fabricated by doctor-blade casting process and wet spinning method, respectively. Scanning electron microscopy (SEM), fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD) and thermogravimetric analysis (TGA) were used to characterize the chemical and physical properties of resulting powder, membrane and fiber. Compared with the raw chicken feather, the regenerated keratin materials retain its chemical structure and thermal stability, their relative crystallinity is a little different depend on the shaping method, which leads to the difference in moisture regain. The mechanical results show that tensile strength of the keratin membrane researches 3.5MPa, have potential application in biomedical fields. However, the keratin fiber presents low tenacity, i.e. 0.5cN/dtex, this problem should be solved in order to apply the new fiber in textile and material science.

Effects of monomers and homopolymer contents on the dry and wet tensile properties of starch films grafted with various methacrylates.

Starch grafted with four different methacrylates was compression molded to form thermoplastic films with good strength and water stability. Starch is an inexpensive and biodegradable polymer but is nonthermoplastic and needs to be chemically modified to make starch suitable for various applications. In this research, starch was grafted with four methacrylates (methyl, ethyl, butyl, and hexyl), and the effect of the length of the alkyl ester group on grafting parameters, thermoplasticity, and properties of thermoplastic films developed have been studied. Influence of grafting conditions on % grafting efficiency, % homopolymers, and % monomer conversion were studied, and the grafted starch was characterized using thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and nuclear magnetic resonance ((1)H NMR). At similar grafting ratios, butyl methacrylate (BMA) provided better strength and elongation to the starch films than the other three methacrylates. Grafting of methacrylates appears to be an economical approach to develop thermoplastic products from starch.

Development and Characterization of Thermoplastic Films from Sorghum Distillers Dried Grains Grafted with Various Methacrylates

Distillers Dried Grains (DDG) obtained during production of ethanol from grain sorghum were grafted with methacrylates and compression molded into films with good dry and wet tensile properties. Since sorghum DDG contains up to 45% proteins that are indigestible by animals, it is necessary to find alternative applications to make sorghum ethanol economically competitive. In this research, sorghum DDG was grafted with methyl, ethyl, and butyl methacrylates, the grafted DDG was compression molded into films, and the properties of the grafted DDG and films were studied. At a grafting ratio of 40%, butyl methacrylate (BMA) grafted films had a strength of 4.8 MPa and elongation of 1.8% when dry and 3.1 MPa and 8.1% when wet, indicating that the films had good strength and wet stability. Films developed from grafted DDG show the potential to overcome the brittleness and poor water stability of biopolymer-based films and be useful for various applications.

Effect of Alkaline Pre-Treatment and Temperature on Cotton Uptake of Sorghum Husk Extract

Sorghum is a staple food around the world. As the demand for the grain soars, there is an equivalent increase in the quantity of sorghum husk generated. Sorghum husk is a promising resource as a natural functional dye. Sorghum is enriched with phytochemicals such as tannins, phenolic acids and anthocyanins which have health benefits. Colorant from the husk was used to dye cotton. Cotton was pretreated with alkaline and dyed at a temperature range of 80°C-130°C. An untreated sample was used as control. The colorant was extracted from Sorghum husk with ultrasound-microwave machine and 70% ethanol//30% water with 1ml HCl per 100 ml as solvent at 55°C for 20 mins. The extraction yield was yield of 16.7%. Ultrasound-microwave-assisted extraction method with blended solvent 70% ethanol/30% water with HCl significantly improved extraction of biocolorants from sorghum husk. The extracted colorant was used to dyed alkaline treated fabric and the fabric had better colorfastness to laundry, crocking and light and better UV protection. The optimum dyeing temperature was 100°C. The use of sorghum husk as a source of colorant can find application in industry and significantly add value to the sorghum plant and reduce the disposal of sorghum husk.

Biodegradable sizing agents from soy protein via controlled hydrolysis and dis-entanglement for remediation of textile effluents

Fully biodegradable textile sizes with satisfactory performance properties were developed from soy protein with controlled hydrolysis and dis-entanglement to tackle the intractable environmental issues associated with the non-biodegradable polyvinyl alcohol (PVA) in textile effluents. PVA derived from petroleum is the primary sizing agent due to its excellent sizing performance on polyester-containing yarns, especially in increasingly prevailing high-speed weaving. However, due to the poor biodegradability, PVA causes serious environmental pollution, and thus, should be substituted with more environmentally friendly polymers. Soy protein treated with high amount of triethanolamine was found with acceptable sizing properties. However, triethanolamine is also non-biodegradable and originated from petroleum, therefore, is not an ideal additive. In this research, soy sizes were developed from soy protein treated with glycerol, the biodegradable triol that could also be obtained from soy. The soy sizes had good film properties, adhesion to polyester and abrasion resistance close to PVA, rendering them qualified for sizing applications. Regarding desizing, consumption of water and energy for removal of soy size could be remarkably decreased, comparing to removal of PVA. Moreover, with satisfactory degradability, the wastewater containing soy sizes was readily dischargeable after treated in activated sludge for two days. In summary, the fully biodegradable soy sizes had potential to substitute PVA for sustainable textile processing.

Degradation and regeneration of feather keratin in NMMO solution

Chicken feather, a potential source of keratin, is often disposed as waste material. Although some methods, i.e., hydrolysis, reduction, and oxidation, have been developed to isolate keratin for composites, it has been limited due to the rising environmental concerns. In this work, a green solvent N-methylmorpholine N-oxide (NMMO) was used to extract keratin from chicken feather waste. Eighty-nine percent of keratin was extracted using 75% NMMO solution. However, the result from size exclusion HPLC showed that most of the keratin degraded into polypeptide with molecular weight of 2189 and only 25.3% regenerated keratin was obtained with molecular weight of 14,485. Analysis of amino acid composition showed a severe damage to the disulfide bonds in keratin during the extraction procedure. Oxidization had an important effect on the reconstitution of the disulfide bonds, which formed a stable three-dimensional net structure in the regenerated keratins. Besides, Raman spectra, NMR, FT-IR, XRD, and TGA were used to characterize the properties of regenerated keratin and raw chicken feather. In the end, a possible mechanism was proposed based on the results.