Synthesis and characterization of hydroxyethyl cellulose copolymer modified polyurethane bionanocomposites.

Bio based polyurethane nanocomposites (renewable thermosets) show a diverse range in properties, processing components and production of smart materials for health, food, and energy sectors. In this work, polyurethane nanocomposites based on isophorone diisocyanate (IPDI), and hydroxyl terminated-polybutadiene (HTPB) incorporating clay were modified using hydroxyethyl cellulose (HLAC) to be further assessed for thermal and mechanical properties. Elastomers samples were prepared by blending clay suspension and PU prepolymer to attain clay contents of 0.3, 0.5, and 1% (weight on dry basis) along with butane diol and HLAC chain extenders. Effect of nanofiller aggregation and dispersion on the thermal degradation and surface morphology of the bionanocomposites were studied. Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy/energy dispersive X-ray (SEM/EDX) and thermal gravimetric (TG) techniques were used to investigate the interactions among PU matrix, clay nanofillers, and HLAC. Mechanical testing indicated an increase in tensile strength and a decrease in elongation at break (%) by just adding 0.3 wt% clay. The thermal stability of the bionanocomposites was improved with the addition of clay. The results of the thermal and mechanical studies demonstrated the feasibility of the bionanocomposites as strong and thermally stable elastomers with low filler loading.

Synthesis and characterization of graphene nanoplatelets-hydroxyethyl cellulose copolymer-based polyurethane bionanocomposite system.

Bionanocomposites is an emerging class of biohybrid materials, have a significant impact in environmental and biomedical fields owing to their high performance, lightweight, unique, and ecofriendly properties. A major challenge in the multiphase bionanocomposites system is to subtle control over the performance by managing the individual properties of reacting components. Herein, we presented the preliminary investigation on bionanocomposite system based on graphene nanoplatelets (GNPs) and hydroxyethyl cellulose graft poly(lactic acid) copolymer-polyurethane (HLAC-PU) with the aim to understand the structure property correlation for proposed applications in electronics and medical areas. The HLAC was fabricated by graft copolymerization of hydroxyethyl cellulose (HEC) and lactic acid (LA) with dibutyltin dilaurate. The HLAC was used to get a bio-functionalized PU matrix reinforced with GNPs by step-growth polymerization method. The structural, surface, and thermal properties of the HLAC and GNPs-HLAC-PU bionanocomposites were studied. The spectroscopic techniques confirmed the structure of bionanocomposites by the identification of related bands. The SEM/EDX results demonstrated that the 0.3 wt% of GNPs dispersed well in the HLAC-PU matrix and offered higher crystallinity. The reinforcement of the 0.3 wt% of GNPs has meaningfully enhanced the thermal stability producing higher residue contents. The reinforced GNPs filler increased the water resistance of bionanocomposites by reducing their water vapor permeability.

Preparation of hydroxyethyl cellulose/halloysite nanotubes graft polylactic acid-based polyurethane bionanocomposites.

2-Hydroxyethyl cellulose graft polylactic acid copolymer (HLAC) was prepared by graft copolymerization of lactic acid (LA) and 2-hydroxyethyl cellulose (2-HEC), initiated by dibutyltin dilaurate (DBTDL) catalyst in aqueous media. Halloysite nanotubes (HNTs)/polyurethane (PU) bionanocomposites were prepared using the HLAC as chain extender in the step-growth polymerization. HNTs were dispersed in HLAC based PU matrix at different weight ratios of 0.30, 0.50, 1.00, and 3.00. Chemical structure and morphology of the graft copolymer and bionanocomposite elastomers were characterized using solid state 1H NMR, ATR-FTIR, XRD, and SEM-EDX, while thermal degradation behavior was studied by TGA and DSC techniques. Surface morphology of the HNTs reinforced HLAC/PU bio-nanocomposites demonstrated the homogeneous dispersion of HNTs with little wavy rough surface at low contents which turned to be brittle at higher contents due to agglomerated HNTs. It is observed that the lower contents of HNTs were completely exfoliated in the HLAC/PU matrix. Crystalline pattern of the elastomers improved at lower contents of HNTs that enhanced the thermal stability of the bionanocomposites. The mechanical testing suggested that HNTs/HLAC/PU bionanocomposites have higher values of tensile strength and % elongation with only 0.3-0.5 wt% contents of HNTs that suggested the potential applications of elastomers at economic cost.

Structural elucidation and biological aptitude of modified hydroxyethylcellulose-polydimethyl siloxane based polyurethanes.

The main aim of this research work was to incorporate modified hydroxyethylcellulose (HEC) into PDMS based polyurethanes. In the first part, modification of hydroxyethylcellulose was carried out by polymerizing lactic acid (LA) with HEC using ammonia water to prepare poly(lactic acid) grafted hydroxyethylcellulose (HEC-g-PLA). The maximum degree of grafting (59.5%) was achieved at: 1:9 mole ratio of HEC/LA, 2 h, 80 °C (for activation) and 4 h, 90 °C (for reaction) with 0.74 degree of substitution. In the second part, hydroxyl terminated polybutadiene (HTPB) was reacted with isophorone diisocyanate to produce NCO-terminated polyurethane prepolymer which in turn extended by chain extender to synthesize polydimethyl siloxane hydroxyl terminated (PDMS) based polyurethanes. Effect of incorporation of HEC-g-PLA as a chain extender was studied by varying its mole ratio in PDMS based PUs. Characterization of HEC-g-PLA and all PDMS/HEC-g-PLA based polyurethane samples was carried out by using Fourier Transform Infrared (FTIR) and proton solid-state NMR (1H SS NMR). Biological behavior of synthesized samples was also tested by various biological activities and results indicated that incorporation of HEC-g-PLA in to PDMS based polyurethanes leads to improvement in antibacterial activity, anti-biofilm inhibition, biocompatibility and non-mutagenicity. Therefore, HEC-g-PLA/PDMS blended polyurethanes are promising biomaterials that have potential for various biomedical applications.

A review on grafting of hydroxyethylcellulose for versatile applications.

Hydroxyethylcellulose (HEC) is a biocompatible, biodegradable, nontoxic, hydrophilic, non- ionic water soluble derivative of cellulose. It is broadly used in biomedical field, paint industry, as a soil amendment in agriculture, coal dewatering, cosmetics, absorbent pads, wastewater treatment and gel electrolyte membranes. Industrial uses of HEC can be extended by the its grafting with different polymers including poly acrylic acid, polyacrylamide, polylactic acid, polyethyleneglycol, polydimethyleamide, polycaprolactone, polylactic acid and dimethylamino ethylmethacrylate. This permits the formation of new biomaterials with improved properties and versatile applications. In this article, a comprehensive overview of graft copolymers of HEC with other polymers/compounds and their applications in drug delivery, stimuli sensitive hydrogels, super absorbents, personal hygiene products and coal dewatering is presented.

Hydroxyethylcellulose-g-poly(lactic acid) blended polyurethanes: Preparation, characterization and biological studies.

The present research project is planned to prepare novel biodegradable and biocompatible hydroxyethylcellulose-g-poly(lactic acid) (HEC-g-PLA) blended polyurethanes. Hydroxyl terminated polybutadiene (HTPB) was reacted with isophorone diisocyanate (IPDI) to produce NCO-terminated polyurethane prepolymer and extended further by varying the mole ratio of chain extenders (HEC-g-PLA and BDO). The synthesized polyurethane samples were characterized by using Fourier Transform Infrared (FTIR), proton solid-state NMR (1H SS NMR) and X-ray diffraction (XRD). Thermal behavior of synthesized samples was checked by using thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). Biological behavior of the synthesized PU samples was also tested by various biological activities which showed much dependence on the mole ratio of chain extenders. Results indicated that incorporation of grafted HEC in to the polyurethane backbone leads to improvement in antibacterial activity, anti-biofilm inhibition, biocompatibility and non-mutagenicity.

A review on versatile applications of blends and composites of CNC with natural and synthetic polymers with mathematical modeling.

Cellulose is world's most abundant, renewable and recyclable polysaccharide on earth. Cellulose is composed of both amorphous and crystalline regions. Cellulose nanocrystals (CNCs) are extracted from crystalline region of cellulose. The most attractive feature of CNC is that it can be used as nanofiller to reinforce several synthetic and natural polymers. In this article, a comprehensive overview of modification of several natural and synthetic polymers using CNCs as reinforcer in respective polymer matrix is given. The immense activities of CNCs are successfully utilized to enhance the mechanical properties and to broaden the field of application of respective polymer. All the technical scientific issues have been discussed highlighting the recent advancement in biomedical and packaging field.

A review on blending of corn starch with natural and synthetic polymers, and inorganic nanoparticles with mathematical modeling.

Maize or corn is considered as very distinctive plant. Corn having better capability of utilizing sun light, is a noble way of getting a natural polymer known as starch. Amylopectin and amylase composition in the starch firmly affects the properties of the polysaccharide. Despite of application of CS as food for living being including the human and animals it has many other applications in industry. No doubt it has many flaws which can be controlled by adopting different modifications. Nowadays bio-degradable polymers are useful which are produced by corn starch. Starch based plastics and composites are not cheap but produce less waste which ultimately reduces the plastic pollution. Different types of natural and synthetic polymers and nano clay can be blended with starch. Some of these polymers are tailor made for some special purposes. Natural polymers like chitosan, cellulose, gelatin, collagen, zein, alginate, Kappaphycus alvarezii seaweed, various amino acids, and synthetic polymers like polybutylene, polyacrylic acid, polyethylene, polyvinyl chloride, polyvinyl alcohol, polycaprolactone, and acrylic acid are utilized to modify starch to yield starch base completely bio-decomposable polymers. These biopolymers have the capability to substitute the petroleum based polymers, and can be used for different environmental, industrial and medical applications.

Subchronic Toxicity Assessment of Orally Administered Methanol (70%) Seed Extract of Abrus precatorius L. in Wistar Albino Rats.

OBJECTIVES: Abrus precatorius L. is a famous medicinal plant of the family Fabaceae and is widely used in traditional medicine for the treatment of various ailments. However, there are limited toxicological data available regarding its safety following repeated exposure; therefore, the present study was designed to evaluate the 28-day subchronic toxicity of methanol (70%) crude extract of A. precatorius seeds in adult Wistar albino rats. MATERIALS AND METHODS: A subchronic toxicity experiment was conducted by oral administration of graded doses (200 mg/kg and 400 mg/kg) of test extract daily for 28 days. Signs of toxicity, food and water consumption, body weight, and gross pathology as well as relative organ weight were evaluated. The toxic effects were also assessed using hematological and biochemical data followed by histopathological examination of various internal organs. All data collected were expressed as mean ± standard deviation. ANOVA followed by the Bonferroni test was used for data interpretation and p<0.05 was considered significant. RESULTS: No deaths or evident toxic signs were found during the experimental period. There were no significant differences in body weight, gross pathology, organ weight, or food and water consumption between the control and the treated groups. There were no treatment-related differences in hematological or biochemical indices. Moreover, no gross abnormalities or histological alterations were observed. CONCLUSION: The methanol extract of A. precatorius seeds was nontoxic in subchronic intake at the dosages tested. Thus, this study is expected to be beneficial for clinical and traditional applications for safe consumption and to utilize A. precatorius as a remedy at a recommended dosage.

A review on versatile applications of blends and composites of pullulan with natural and synthetic polymers.

Pullulan is a non-ionic, linear, water-soluble and a neutral polysaccharide. It is composed of α-(1,6) repeated maltotriose units via α-(1,4) glycosidic bond having chemical formula (C6H10O5)n. It shows non-immunogenic, non-toxic, non-carcinogenic and non-mutagenic properties. It is used in food edible coatings, films, as flocculant, foaming agent and adhesive. It may also be used as a carrier for bioactive compounds and a protective packaging for food and pharmaceutical products. Therefore, it is blended with different polymers such as carrageenan, mucilages, chitosan, cellulose, sodium alginate, starch, polyethyleneimine, whey-protein, polyisopropylacrylamide, histone, jeffamine, polyamidoamine, pemulen, hyaluronic acid, polyvinyl alcohol and caboxymethyl cellulose. In this article, a comprehensive overview of combination of pullulan with natural and synthetic polymers and their applications in biomedical field involving drug delivery system, tissue engineering, wound healing and gene therapy, is presented. It also describes the utilization of pullulan based materials in food industry, water treatment and pharmaceutical industry. All the technical scientific issues have been addressed; highlighting the recent advancements.

Synthesis and characterization of chitin/curcumin blended polyurethane elastomers.

In this work, chitin-curcumin based polyurethane elastomers (PUEs) were prepared by step growth polymerization technique using hydroxy terminated polybutadiene (HTPB), hexamethylene diisocyanate (HDI), chitin and curcumin. The molecular characterization was done by using FTIR and SS 1HNMR techniques. The surface morphology and thermal stability was studied by scanning electron microscopy (SEM) and thermal gravimetric analysis (TGA), respectively. Degree of absorption and swelling characters were also determined in water as well as in DMSO. The crystalline behavior of prepared elastomers was checked by using X-ray diffraction (XRD) and differential scanning calorimeter (DSC). Results presented that crystallinity of elastomers increased by increasing the content of chitin due to formation of more ordered structure.

Recent trends on gellan gum blends with natural and synthetic polymers: A review.

Gellan gum (GG), a linear negatively charged exopolysaccharide,is biodegradable and non-toxic in nature. It produces hard and translucent gel in the presence of metallic ions which is stable at low pH. However, GG has poor mechanical strength, poor stability in physiological conditions, high gelling temperature and small temperature window.Therefore,it is blended with different polymers such as agar, chitosan, cellulose, sodium alginate, starch, pectin, polyanaline, pullulan, polyvinyl chloride, and xanthan gum. In this article, a comprehensive overview of combination of GG with natural and synthetic polymers/compounds and their applications in biomedical field involving drug delivery system, insulin delivery, wound healing and gene therapy, is presented. It also describes the utilization of GG based materials in food and petroleum industry. All the technical scientific issues have been addressed; highlighting the recent advancement.

Morphological and thermal studies of chitin-curcumin blends derived polyurethanes.

The present study describes a novel ecofriendly series of chitin/curcumin/1,4-butane diol (BDO) blend derived polyurethanes (PUs), using hydroxy terminated polybutadiene (HTPB) and hexamethylene diisocyanate (HDI) along with different mole ratio of chitin, curcumin and BDO. The structural and morphological elucidation of the prepared films was done by FTIR and SEM techniques. The swelling behavior of the films was analyzed in both water and DMSO, which showed that incorporation of chitin increases the hydrophobicity and decreases the rate of swelling. Thermal analysis of synthesized PU blends revealed better thermal stability with following mole ratio 1:0.5:0.5 of chitin: curcumin: BDO as determined by TGA and DSC techniques.

Pectins functionalized biomaterials; a new viable approach for biomedical applications: A review.

Pectins are natural complex heteropolysaccharides, composed of (1, 4)-linked α-d-galacturonic acid residues and variety of neutral sugars such as rhamnose, galactose and arabinose. It is second most abundant component of the cell wall of all land plants. It has wide applications in various fields due to its use as gelling, emulsifying or stabilizing agent and as well as its non-toxic, biocompatible and biodegradable nature. Considering these versatile properties this review sheds a light on the synthesis, modification, characterization and applications of pectin based polymers. Most of them are used in industries, pharmaceutics, nutraceutics, drug delivery, tissue engineering, food packaging and cosmetics. Properties of pectin can be improved and modified by forming derivatives, blends and composites.

Glycoproteins functionalized natural and synthetic polymers for prospective biomedical applications: A review.

Glycoproteins have multidimensional properties such as biodegradability, biocompatibility, non-toxicity, antimicrobial and adsorption properties; therefore, they have wide range of applications. They are blended with different polymers such as chitosan, carboxymethyl cellulose (CMC), polyvinyl pyrrolidone (PVP), polycaprolactone (PCL), heparin, polystyrene fluorescent nanoparticles (PS-NPs) and carboxyl pullulan (PC) to improve their properties like thermal stability, mechanical properties, resistance to pH, chemical stability and toughness. Considering the versatile charateristics of glycoprotein based polymers, this review sheds light on synthesis and characterization of blends and composites of glycoproteins, with natural and synthetic polymers and their potential applications in biomedical field such as drug delivery system, insulin delivery, antimicrobial wound dressing uses, targeting of cancer cells, development of anticancer vaccines, development of new biopolymers, glycoproteome research, food product and detection of dengue glycoproteins. All the technical scientific issues have been addressed; highlighting the recent advancement.

A review on synthesis, properties and applications of natural polymer based carrageenan blends and composites.

Carrageenan is a natural polysaccharide extracted from edible red seaweeds of Rhodophycea class. It has been used as a viscosity increasing or gelling agent for prolonged and controlled drug release, food, pharmaceuticals and other industries. However, in spite of wide range of applications, carrageenan has some drawbacks and adverse effects on the biological systems, so its modifications with natural and synthetic polymers are carried out. This review article presents different sources and properties of carrageenans with special emphasis on natural polymer based carrageenan blends and composites and their applications in controlled drug delivery system, wound dressing and tissue engineering because of their biodegradability and biocompatibility, food industry as thickening/gelling materials, cosmeceuticals and making polyelectrolyte complexes.

Blends and composites of exopolysaccharides; properties and applications: A review.

Exopolysaccharides are synthesized by bacteria and secreted into the external environment and they may be homopolymeric or heteropolymeric in configuration. They are believed to protect bacterial cells from heavy metals, desiccation or other environmental effect. EPS exhibit antitumor, anti-HIV, emulsion stabilization capacity, shear-thinning activity, suspension ability, high viscosities, excellent biocompatibility, high biodegradability and immunomodulatory properties. They are widely used in herbicides, functional food, nutraceuticals, cosmeceuticals, pharmaceuticals, insecticides, immunomodulation and anticoagulants. This review shed light on the properties and versatile applications of xanthan, curdlan, hyaluronic acid and dextran blends and composites with natural and synthetic polymers.

Polysaccharide based bionanocomposites, properties and applications: A review.

Bio-nanocomposites, composed of biopolymers and inorganic solids, show dimensions in the nanometer range (1-100nm) which can be widely used in variety of areas owing to multidimensional properties like biocompatibility, antimicrobial activity and biodegradability. Considering these versatile properties of the bio-nanocomposites this review sheds a light on the synthesis, modification, characterization and applications of bio-nanocomposites based on different polysaccharides functionalized by different nanofillers such as MMT, Ag, SiO2, TiO2, and ZnO. Most of them have been used in regenerative medicine, drug delivery, tissue engineering, electronics and food packaging. The modification of clays with biopolymers results an attractive alternative in the development of environmentally friendly materials for pollutants removal. All the technical scientific issues have been addressed highlighting the recent advancement.

Synthesis and characterization of chitosan/curcumin blends based polyurethanes.

In this work, new hexamethylene diisocyanate (HMDI) and hyroxylterminated polybutadiene (HTPB) based polyurethanes (PUs) were prepared following step growth polymerization by the introduction of varying mole ratio of chitosan (CH) and curcumin (CUR). Structural study of blends through infrared spectroscopy confirmed the incorporation of CH and CUR into the backbone of the PU. The scanning electron microscopic (SEM) study confirmed the well dispersion of incorporated chitosan/curcumin and homogeneity of surface of synthesized samples. Thermogravimetric analysis (TGA) of PU blends indicated a better thermal stability with 0.25M:0.75M of chitosan to curcumin. Mechanical properties such as modulus and tensile strength of PU blends were found to be better with higher contents of chitosan and curcumin. The same extender composition (1mol BDO, 075mol chitosan and 0.25mol curcumin) based PU showed higher substantial of antimicrobial activity as compared to the all other PUs. On the whole, this work is actually a step towards the generation of novel biocompatible materials preferably useful for biomedical applications.

Lignin-derivatives based polymers, blends and composites: A review.

Lignin and lignin derivatives biopolymers have several properties, such as high thermal stability, antioxidant, biodegradability, antimicrobial actions, adhesive properties, etc., and thus they can be extensively used in wide range of areas. Although human history mostly depend on the biopolymers, however derivatives of lignin such as sulfonate, phenolic, organosolv, Kraft and sodium sulfonate lignin have good mechanical and physicochemical properties. Well-designed materials such as coatings and paints, manufacturing of plastics and resins, for rubber packaging, for fuel production etc., can be obtained by the functionalizations of chemically modified lignin. Considering multi purposes properties of the lignin and lignin derivatives and extensive industrial applications of derivatives, this review sheds a light on lignin derivatives based materials with their prospective applications. All the technical scientific issues have been addressed highlighting the recent advancement.