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Keratin particles with microscale are prepared by ball mill and its influences on the chitosan membrane is evaluated. Composite membranes with various content of keratin are fabricated, and their physical and chemical properties such as morphology, wettability, crystallization, thermal stability, tensile strength, and break elongation are investigated. Optical microscope and situ topographic scan mode of nano-test system are used to examine the dispersion and aggregation of keratin on the surface of chitosan membrane. The result of contact angle (CA) and mechanical testing show that the incorporation of keratin particles decrease the CA from 98.1 ° to 58.2 °. Tensile strength and break elongation of the composite membrane reaches a maximum of 65 ± 8 MPa and 15% when the keratin content is 6%, an increase of 80% and 88% compared with the pristine chitosan membrane. Both the increase in tensile strength and break elongation is result of the incorporation of keratin particles known for their excellent compatibility between keratin and chitosan matrix. These kind of composite material combines the antibacterial properties of chitosan with cell culture preference of keratin which may have potential biomedical application. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 134, 44667.

Films developed by thermoprocessing of plant proteins have better mechanical properties and are relatively inexpensive and environmentally friendly compared to casting films from solutions. Common plant proteins such as soyproteins, wheat gluten, and corn zein and proteins from lesser grown cereal crops such as peanut, barley, sunflower, and sorghum have all been injection or compression molded into films. Since plant proteins are non-thermoplastic, it is necessary to chemically or physically modify the proteins and make them thermoplastic. Extensive studies on the addition of plasticizers, pre-treatment of proteins with alkali, steam, chemical modifications such as acetylation and blending of the proteins with other biopolymers and synthetic polymers have been done to modify proteins and develop thermoplastics. Despite the extensive work, thermoplastic films obtained from plant proteins do not have the properties that can meet or exceed properties of films made from synthetic polymers. Poor water stability and brittleness are the two major limitations of plant protein films. This review presents an overview of the methods and processing conditions used to develop thermoplastic films from plant proteins and the properties of the films. A critical assessment of approaches that have been used so far, limitations of these approaches and potential considerations for future studies to overcome the current limitations have been discussed. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 729-738, 2013

High- density polyethylene (HDPE) in used plastic bags was reinforced with chicken feathers to develop composites in an effort to add value and reduce the amount of the plastics and feathers disposed in landfills. Feathers are biodegradable, derived from renewable resource, and are inexpensive and HDPE in plastic bags is mostly discarded in landfills. Utilizing feathers as reinforcement for HDPE composites will provide an opportunity to develop environmentally friendly composites. In this research, HDPE plastic bags were reinforced with chicken feathers and the flexural, tensile and acoustic properties were studied. It was found that incorporating feathers substantially improved the flexural properties and tensile modulus. At the optimum condition, the HDPE-feather (50/50) composites had flexural strength of 13.9 MPa and stiffness of 0.45 N/mm compared to 9.8 MPa and 0.29 N/mm for 100% HDPE. The 50/50 HDPE-feather composite had similar tensile strength but more than twice the tensile modulus of neat HDPE. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

Curcumin, a yellow pigment known to have various biological activities, was applied onto cotton as an antimicrobial agent. Curcumin could provide both color and antimicrobial activity to cotton and can be dyed using a batch or continuous process. However, curcumin and cotton have low affinity and therefore the ability of curcumin to impart durable antimicrobial activity on cotton needs to be studied. In this research, the ability of curcumin dyed onto cotton fabrics to inhibit the growth of Escherichia coli and Staphylococcus aureus was studied. Relationships that can predict the rate of inhibition based on the curcumin concentration or shade depth (K/S values) were developed without the need for an antimicrobial test. Durability of antimicrobial activity to laundering and to light was also studied. Curcumin was more effective in inhibiting S. aureus than E. coli. The reduction of bacteria and durability of antimicrobial activity of curcumin to laundering was inferior on cotton fabrics compared with wool. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

The ability of polylactide (PLA) to retain its mechanical properties after repeated cleanings at various pH levels, washing temperatures, and drying conditions has been studied. One of the problems with PLA is its poor resistance to hydrolysis, especially under alkaline conditions. In this study, PLA fabrics were sent through 50 cleaning cycles with different pH levels (8 or 10), washing temperatures (35 or 55°C), and drying conditions (air dry at 21°C/65% relative humidity or tumble dry at 50 or 70°C). The retention percentages of the breaking tenacity, breaking elongation, and modulus of the PLA yarns were measured after every 10 cleaning cycles. A pH of 8 gave greater breaking tenacity, breaking elongation, and modulus retention than pH 10. Washing PLA at 35°C and air drying it at 21°C resulted in greater modulus retention than washing and drying at higher temperatures. Hydrolysis of the polymer was the main cause of the loss in mechanical properties. Equations were developed to predict the retention percentage of the breaking tenacity, breaking elongation, and modulus based on the pH, number of cleaning cycles, and washing and drying temperatures. Recommendations for appropriate conditions for the cleaning of PLA fabrics that result in greater mechanical property retention are given. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008

The solubility parameters of polylactide (PLA), poly(ethylene terephthalate) (PET), and various disperse dyes calculated according to the group contribution method were used to explain the low sorption of some disperse dyes on PLA but the high sorption of the same dyes on PET. It was found that the dyes with high sorption on PLA tended to have solubility parameters near that of PLA, which has a lower solubility parameter than that of PET. It was also found that the solubility parameter, which was calculated based on cohesive energy and molar volume at 25°C, was more appropriate for explaining dyeings at lower temperature, 100 and 110°C, than those at higher temperature, 130°C. Based on the finding that dyes with solubility parameters near that of PLA tend to have high sorption on PLA, general structures for disperse dye that may have high sorption on PLA were proposed. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 416–422, 2005

Polypropylene–clay nanocomposites were prepared by a solution technique and a subsequent melt-mixing process. A titanate coupling agent was used to improve the compatibility of the nanoclay particles with the polypropylene. The dispersion of the nanoclay particles in polypropylene was studied with X-ray diffraction (XRD) and transmission electron microscopy (TEM). An increased d-spacing value of the clay particles in the nanocomposites was observed, and it was compared with the values of as-mined (pristine) and as-received (organophilic) clay particles. The number of intercalated layers in a single clay crystallite was determined to be 4, and the number was confirmed with XRD data and TEM images. On the basis of the Daumas–Herold model (which is widely used for graphite intercalation compounds), the stage 2 and stage 3 structures of montmorillonite particles in polypropylene were recommended. A study on the stage structure suggested a way of determining the presence of polymer molecules in the clay galleries. The results confirmed the existence of single-layered platelets with improved dispersion in polypropylene. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 218–226, 2005

Starch acetate–corn fiber foams were prepared by extrusion. Corn starch was acetylated (DS 2) to introduce thermoplastic properties. Corn stalks were treated with sodium hydroxide to remove the lignin and to obtain purified cellulose fibers. Starch acetate was blended with treated fiber at concentrations of 0, 2, 6, 10, and 14% (w/w) and extruded in a corotating twin-screw extruder with 12 to 18% w/w ethanol content and 5% talc as a nucleating agent. The samples were extruded at 150°C and selected physical and mechanical properties were evaluated. Micrographic properties were analyzed using scanning electron microscopy to observe the interaction of fiber and starch. Fiber incorporation at the lower concentrations enhanced the physical properties of the foams. Fiber contents greater than 10% decreased expansion and increased density and shear strength. Good compatibility between starch and corn fiber was observed. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 2627–2633, 2004

The chemical modification of soy protein isolate (SPI) with various amounts of oxidized sucrose was performed in this study. The poor mechanical properties and lack of hydrolysis resistance of SPI have limited its applications in various fields. Although chemical modification proved to be an effective method to enhance the properties of SPI films, current SPI modifiers are either expensive, toxic, or do not impart the satisfiable properties to the modified materials. In this research, the possibility of modification of SPI films using oxidized sucrose to improve their strength and stability was examined. At optimal conditions, oxidized sucrose-modified SPI films showed about 50% higher wet strength than the control films. The melting temperature of modified SPI film was 26°C higher than the unmodified control. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41473.

Wool powders with low solubility could be easily prepared from wool fibers by combining hydrothermal pretreatment (HTP) and grinding processes. Transforming wool fibers into powders was the first step of exploiting wool as new materials such as bio-thermoplastics. However, wool fibers were difficult to be prepared into powders only by grinding due to their toughness. This article used a chemical-free method to obtain wool powders by grinding HTP-treated wool fibers. Wool fibers after HTP at 130°C for 40 min or above were obviously easier to be broken into snippets with lengths of 25–150 μm after grinding for 1 min and shapeless super-fine powders with diameters of 3–15 μm after ball milling for 10 min. Wool fibers after HTP were brittle mainly owing to decrease of α-helices and SS bonds. Combination of HTP and grinding could be an eco-friendly and feasible treatment to prepare wool powders on industrial scale. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40173.

A novel dry-spinning method for the preparation of zein fiber without using formaldehyde is presented. The fiber thus obtained had good stability to boiling aqueous acetic acid solution with breaking tenacity and elongation of 1.0 g/d and 30%, respectively. Citric acid and butanetetracarboxylic acid were used as nonformaldehyde crosslinking agents for the preparation of zein fiber successfully. Using polycarboxylic acids have advantages such as no toxicity and low sensitivity to the variation of processing conditions over formaldehyde containing stabilizers. The effects of crosslinking before and after stretching on improvement of fiber properties were discussed. Fiber morphological structure was also examined by means of wide angle x-ray diffraction and sonic velocity. © 1996 John Wiley & Sons, Inc.

A modified Donnan model is discussed with consideration of physical interactions in the ion sorption by polyamide as a function of the influence of ions in the system. Lyotropic numbers and the salt effect on water-structure changes are considered to describe their influence on the physical interactions between the sorbate and the sorbent. It is found that some electrolytes, such as sulfates and phosphates, can increase the sorption of some negatively charged ions (e.g., acid dyes) on positively charged polyamide it salt concentration is high (e.g., > 0.5 M), after the initial decrease of ion sorption at a low salt concentration range. This result is difficult to explain by the model that treats all interactions other than ionic interaction as a constant. The modified Donnan model explains both the decrease and increase of ion sorption with increasing salt concentration quantitatively. © 1994 John Wiley & Sons, Inc.

Whole hop bines (HBs), the peeled outer bark (OB) of HBs, and fibers chemically extracted from hop bark (HFs) were used as reinforcements to make lightweight composites with polypropylene (PP) webs or fibers as the matrix materials. Using discarded HBs for composites not only increases the value of hop crops but also provides a green, sustainable, and biodegradable material for the composite industry. Lightweight composites are preferred, especially for automotive applications because of the potential energy savings. In this research, the effects of the processing parameters on the properties of PP composites reinforced with HBs were studied. The composites reinforced with OB without any chemical treatment showed better properties than the composites reinforced with HFs or HBs. Compared with jute–PP composites of the same density (0.47 g/cm3), composites reinforced with OB had 43% higher flexural strength, 46% higher impact resistance, 56% higher Young's modulus, similar modulus of elasticity, 33% lower tensile strength, and better sound-absorption properties. OB–PP composites with optimized properties have the potential to be used in industrial applications such as support layers in automotive interiors, ceiling tiles, and office panels. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010

Light-weight composites reinforced with whole chicken feathers have better flexural strength than composites reinforced with feather fibers (barbs) and nearly thrice higher tensile strength and seven times higher tensile modulus than composites reinforced with powdered chicken feather quill. Chicken feathers are not only inexpensive and abundantly available but also have unique properties such as low density and hollow centers that make them preferable as reinforcement materials, especially for light-weight composites. However, the traditional methods of developing composites do not provide the flexibility of using feathers in their native form as reinforcement. So far, the components in feathers such as barbs or quills have been used separately and/or feathers have been mechanically processed to destroy their native form in order to use feathers as reinforcement in composites. A new method of making composites using nonwoven webs as matrix allows the incorporation of reinforcing materials in their native form such as whole chicken feathers to develop composites. This research shows that whole chicken feathers can be used as reinforcement in composites with better flexural, tensile, and acoustic properties than composites made from processed chicken feathers. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010