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Oligocellulose (OC) with low polydispersity indices has been produced in large quantities using an improved method of acid-assisted hydrolysis, in which long cellulose chains disintegrate in concentrated phosphoric acid at moderately elevated temperatures. The hydrolysis time has been reduced by three orders of magnitude without compromising the overall yield of the process or the quality of OC products. The efficient production of high-quality OCs in large quantities allows for developing OC-derived elastomeric materials. A series of OC- graft -poly(isobornyl methacrylate- random - n -butyl acrylate) [OC- g -P(IBOMA- r -BA)] elastomers have been synthesized via activators regenerated by electron transfer for atom transfer radical polymerization (ARGET ATRP). OC- g -P(IBOMA- r -BA) elastomers have tunable molecular architectures and phase morphologies toward desirable mechanical properties and thermal stability suitable for various applications. The methodologies of the OC production and the graft -polymers synthesis in this study would help advance technologies for broader applications of bio-based elastomers. [Display omitted] [ABSTRACT FROM AUTHOR]

We developed layered silicate nanocomposite films based on corn starch (CS) and bentonite nanoclay, plasticized with glycerol. The films were elastomeric with stretchability of ca. 60–90 % and T g = −75 to −85 °C. The nanocomposites were exfoliated if c bentonite < 2 wt%, and intercalated if c bentonite > 3 wt%. The exfoliated morphology induced thermal stability as shown by TGA. Interestingly, bentonite induced a reduction of T g while increasing the Young's modulus E and reducing the extensibility. The fracture energy was a decreasing function of c bentonite except at 2.9 wt%, where the nanocomposite exhibited maximum Young's modulus and toughness, as demonstrated by the Ashby-style plot. The nanocomposite films were biodegradable in anaerobic and aerobic conditions, and in anaerobic conditions the intercalated nanocomposite of c bentonite = 2.9 wt% exhibited slower rate of degradation. These results provide insights into the development of bio-degradable elastomeric food packaging and coatings suitable for sub-ambient conditions. [Display omitted] [ABSTRACT FROM AUTHOR]

The convenient and environmentally friendly method for in vitro polymerization catalyzed by glucosyltransferase, designated as GtfJ, extracted from recombinant E. Coli was used to synthesize tailor-made α-1,3-glucan (α-1,3- d -glucan) having moderate molecular weight (M w = 2.0 × 10 5 ) and no branches. With the aim to improve thermoplasticity of this polysaccharide, after in vitro synthesis, chemical modification by acylation was selected and then fully substituted α-1,3-glucan esters were successfully obtained via both homogeneous and heterogeneous methods. Thermal degradation temperature of α-1,3-glucan esters was improved after esterification and dependent on neither side chain length nor synthesis methods. DSC curves suggested a presence of crystal structure in α-1,3-glucan acetate, propionate, butyrate, valerate and hexanoate due to detectable melting endotherm, whereas octanoate exhibited amorphous behavior. T m ’s of α-1,3-glucan esters were relatively high, more than 200 °C, in comparison with commercial plastics. The shorter chain length of acid component, the higher T m and T g ester products exhibited. In addition, tensile strength of α-1,3-glucan esters decreased in contrast with elongation at break with an increase in alkyl chain length of an acid component. Thus, crystalline and amorphous α-1,3-glucan esters with adjustable thermal and mechanical properties obtained from this research are promising materials for continuing applied researches and contemplating the future application in bio-based thermoplastic materials. [ABSTRACT FROM AUTHOR]

This research determined the effects of starch concentration (3.5–5.0%w/w), and plasticizer [glycerol (0–30%w/w) or sorbitol (0–60%w/w)] on properties of mung bean starch (MBS) films. The result showed that increasing plasticizer concentration tended to decrease tensile strength (TS), elastic modulus (EM) and oxygen permeability (OP); but increase elongation (%E), solubility, water vapor permeability (WVP) and seal strength. The extent of those changes also depended on starch concentration. Glycerol provided better plasticizer efficiency than sorbitol. A bimodal melting endotherm of retrograded structure was evident in non-plasticized film. However, only a low temperature endotherm was observed in polyol-plasticized films, indicating a plasticizer-induced structural modification. The developed ductile MBS films, (TS of 7.14 ± 0.95 to 46.30 ± 3.09 MPa, %E of 2.46 ± 0.21 to 56.95 ± 4.34% and EM of 16.29 ± 3.40 to 1428.45 ± 148.72 MPa) with an OP of 0.2397 ± 0.0365 to 1.1520 ± 0.1782 cc mm/m 2 day kPa and seal strength up to 422.36 ± 7.93 N/m, demonstrated in this study indicate the potential for food packaging applications. [ABSTRACT FROM AUTHOR]

In the present work, synthesis of poly(vinyl alcohol)/graphene oxide/starch/silver (PVA/GO/Starch/Ag) nanocomposites films is reported. Such films have been characterized and investigated for their mechanical, thermal and antimicrobial properties. The exfoliation of GO in the PVA matrix occurs owing to the non-covalent interactions of the polymer chains of PVA and hydrophilic surface of the GO layers. Presence of GO in PVA and PVA/starch blends were found to enhance the tensile strength of the nanocomposites system. It was found that the thermal stability of PVA as well as PVA/starch blend systems increased by the incorporation of GO where strong physical bonding between GO layers and PVA/starch blends is assumed to cause thermal barrier effects. Antimicrobial properties of the prepared films were investigated against Escherichia coli and Staphylococcus aureus . Our results show enhanced antimicrobial properties of the prepared films where PVA-GO, PVA-Ag, PVA-GO-Ag and PVA-GO-Ag-Starch showed antimicrobial activity in ascending order. [ABSTRACT FROM AUTHOR]

Starch based wood nanocomposites (WSNC) were prepared successfully from starch and soft wood with multi-walled carbon nanotube (MWCNT) as nano reinforcing agent through a completely green path. The most important part of this scheme was the use of water as the solvent. In this technique, starch was grafted with methylmethacrylate (MMA) and MWCNT was functionalised with hydroxyl groups ( f -MWCNT). Dimethyloldihydroxyethyleneurea (DMDHEU) was used as a cross-linker to prepare the green material from methylmethacrylate grafted starch (MMA- g -starch), soft wood flour and functionalised MWCNT. The functionalization of MWCNT was confirmed by Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA) and Raman analysis. Different properties of the WSNC were investigated by varying the concentration of f -MWCNT. The prepared nanocomposites exhibited outstanding thermal stability, mechanical properties and water resistance capacity compared to untreated wood composites. The flammability of the wood composites decreased up to 30% with just addition of 0.50 phr f -MWCNT. [ABSTRACT FROM AUTHOR]

The surface functionalization of cellulose nanocrystals (CNC) is crucial for promoting their diverse applications, especially regarding their use as sustainable biobased polymer reinforcements. In this study, we develop poly (vinyl alcohol) (PVA)–CNC composites with improved tensile strength and gas-barrier performance using CNC-based nanofillers. Acrylated CNCs (ACNCs) were prepared from cellulose via one-pot acid hydrolysis/Fischer esterification; subsequently, surface modification was performed through a thiol–ene reaction to obtain surface-thiolated ACNCs, namely, DACNC, MACNC, and PACNC. The various functional groups on the surface-thiolated ACNCs not only affect the dispersion stability but also alter their interfacial interactions with the PVA matrix, thus realizing the PVA nanocomposites with tailored properties, including the thermal properties, mechanical properties, and gas barrier performance. This study demonstrates that surface-thiolated ACNCs with appropriate surface chemistry and loading levels can serve as excellent nanofillers for PVA, forming biobased composites with desired properties. [Display omitted] [ABSTRACT FROM AUTHOR]

The AlCl 3 ·6H 2 O aqueous solution was used to dissolve chitosan (CS) and the CS/poly(vinyl alcohol) (PVA) blend films were prepared at the absence of acetic acid. AlCl 3 ·6H 2 O was retained in CS/PVA film and glycerol was added to form the complex plasticizer with AlCl 3 ·6H 2 O. The effect of glycerol on the water sorption, crystalline, thermal and mechanical properties of AlCl 3 ·6H 2 O doped CS/PVA film was studied by atomic force microscopy, X-ray diffraction, thermal gravity analysis and tensile testing, respectively. The experimental results showed that glycerol had a significant positive effect on the properties of AlCl 3 ·6H 2 O doped CS/PVA films. With the synergism effect of AlCl 3 ·6H 2 O and glycerol, the prepared CS/PVA films showed excellent mechanical properties. With the addition of 30 wt% glycerol, the AlCl 3 ·6H 2 O doped CS/PVA films behave the tensile strength of 39 MPa and elongation at break of 120%, respectively. [ABSTRACT FROM AUTHOR]

Nanocrystalline cellulose (CNC), obtained by sulphuric acid hydrolysis, was used to synthesize polyurethane foams (PUFs) based on a functionalized castor oil polyol and a Methylene diphenyl diisocyanate (MDI). Formulations with varying isocyanate index (FI) and NCO number were prepared. At 0.5 wt.%, SEM’s of the fractured surface underlined that the CNC acted both as a nucleation agent and as a particulate surfactant with cell geometries and apparent density changing selectively. The chemical structure of the PUF (FTIR) changed after the incorporation of CNC by a relative change of the amount of urea, urethane and isocyanurate groups. A low NCO number and isocyanate index contributed to the migration of the CNC to the Hard Segment (HS), acting as reinforcement and improving substantially the compressive mechanical properties ( E c and σ c improvements of 63 and 50%, respectively). For a high NCO number or isocyanate index, the CNC migrated to the Soft Segment (SS), without causing a reinforcement effect. The migration of the CNC was also detected with DSC, TGA and DMA, furtherly supporting the hypothesis that a low NCO number and index contributed both to the formation of a microstructure with a higher content of urethane groups. [ABSTRACT FROM AUTHOR]

The effects of surfactant addition to ethyl-cellulose (EC) based oleogels were examined with respect to the chemical nature of the “head” and “tail” groups of the surfactant. Unique sigmoidal temperature dependent rheological behavior was observed upon surfactant addition, suggesting additional organized structure formation. Glycerol-based surfactant addition lead to greatest decrease in the sol–gel and gel–sol transition temperatures compared to sorbitan-based surfactants. This behavior can be attributed to the plasticizing nature of the small head group of glycerol compared to the larger head group of sorbitan surfactants. A significant increase in the penetration force of the gels was observed upon surfactant addition, suggesting possible surfactant–polymer interactions which stiffen the polymer network. Thermal analysis detected a reduction in both SMS and GMS crystallization peak temperature and enthalpy. In the case of GMS, two melting peaks were observed upon EC addition to the oil phase, suggesting EC/surfactant interactions. These results demonstrate the effects of surfactant head group structure on EC oleogel rheological properties. [ABSTRACT FROM AUTHOR]

Polymer composite has contributed tremendously for energy efficient technologies in automotive and aero industries. Environmental and health concerns related to the carcinogenic nature of artificial fiber in polymer composite needs a retrofit. Eco friendly natural cellulosic fiber extract from the stem of Cissus quadrangularis plant is extensively characterized to consider as a viable alternative for man-made hazardous fibers. Anatomical study, chemical analysis, physical analysis, FTIR, XRD, SEM analysis and thermo gravimetric analysis were done to establish the certainty of using them as reinforcement fiber. Its light weight and the presence of high cellulose content (82.73%) with very little wax (0.18%) provide high specific strength and good bonding properties in composite manufacturing. The flaky honeycomb outer surface revealed through electron microscopy contributes for high modulus in CQ stem fiber and thermo gravimetric analysis ensures thermal stability up to 270 °C, which is within the polymerization process temperature. [ABSTRACT FROM AUTHOR]

In this work we report novel chitosan–carbon dots nanocomposite hydrogel films. A new green source “tea” was used as precursor for carbon dots (CDs). The electrostatic interaction of positive charge on chitosan and negative charge on CDs prepared from tea was used for the successful preparation of a stable and robust chitosan–carbon dots nanocomposite hydrogel film. The hydrogel films were characterized by UV–visible spectroscopy, X-ray diffraction (XRD), Fourier transformed infra-red spectroscopy (FTIR), scanning electron microscope (SEM), fluorescent microscopy, thermogravimetric analysis (TGA) and contact angle analysis. It was observed that chitosan–carbon dots hydrogel films are soft but tough with superior UV–visible blocking, swelling, thermal and mechanical properties in comparison to chitosan hydrogel film. Moreover chitosan–carbon dots films are more water repellent (hydrophobic) as indicated by their high contact angle values. Thus, fabrication of such green soft but tough biocompatible chitosan–carbon dots nanocomposite hydrogel films offers tremendous bio-medical and industrial applications. [ABSTRACT FROM AUTHOR]

Xylan-rich hemicellulose from corn cob has been used for new material elaboration. Commercial cellulose was used as reinforcement in different percentages to improve properties of the films. Two types of composites were elaborated by solvent casting.Hydrophilic films, composed by bleached hemicellulose (BH), unmodified cellulose and glycerol as plasticizer, andhydrophobic filmsformed by acetylated bleached hemicellulose (BAH) and acetylated cellulose. The degree of substitution of BAH was 1.8 and acetylated cellulose presented a degree of substitution of 0.54. Thermal and mechanical properties of films were analyzed. A significant improvement was observed in the thermal behavior of hydrophobic films (Tmax~368°C) respect to hydrophilic films (Tmax~300°C). Although the addition of cellulose clearly increase the properties of both type of films, hydrophobic films (Young's modulus ~2300MPa, strength ~44.1MPa, strain at break ~5.7%) showed better mechanical properties than hydrophilic films (Young's modulus ~3MPa, strength ~3.3MPa, strain at break ~5.3%). [ABSTRACT FROM AUTHOR]

Highlights: [•] Edible hydrocolloid film from LPSG was successfully prepared by incorporation of glycerol. [•] Mechanical properties of the films improved as the glycerol content increased. [•] LPSG could be a promising carbohydrate for food packaging. [•] Glycerol was compatible with LPSG and confirmed the effectiveness of plasticization. [ABSTRACT FROM AUTHOR]

Abstract: Cellulose nanocrystals have been prepared by acid hydrolysis of Luffa cylindrica fibers. The acid-resistant residue consisted of rod-like nanoparticles with an average length an diameter around 242 and 5.2nm, respectively (aspect ratio around 46). These cellulose nanocrystals have been used as a reinforcing phase for the processing of bio-nanocomposites using polycaprolactone (PCL) as matrix. To promote interfacial filler/matrix interactions the surface of cellulose nanocrystals was chemically modified with n-octadecyl isocyanate (C18H37NCO). Evidence of the grafting was supported by infrared spectroscopy and elemental analysis. X-ray diffraction analysis was used to confirm the integrity of cellulose nanocrystals after chemical modification. Both unmodified and chemically modified nanocrystals were used to prepare nanocomposites. The thermal properties of these materials were determined from differential scanning calorimetry and their mechanical behavior was evaluated in both the linear and non-linear range. [Copyright &y& Elsevier]

Abstract: Natural cellulose fabrics were newly identified from the branches of the Cordia dichotoma. The structure of the fabrics was analysed by FTIR and X-ray diffraction. The net-like morphologies of the untreated, bleached and 5% NaOH (alkali) treated lignocellulose fabrics were observed by SEM and POM. The increase in thermal stability of alkali treated fabrics when compared to the untreated and bleached fabrics was confirmed by the TGA analyses. The effect of bleaching and alkali treatment on the properties of the fabrics was also studied. The alkali treated fabrics exhibited the highest tensile strength of 36.2MPa, elongation at break of 2% and Young''s modulus of 3699.2MPa when compared to the untreated and bleached fabrics. The structure and properties of the fabrics indicated that they could be suitable for blending and processing with biodegradable polymers to make green composites for various types of applications. [Copyright &y& Elsevier]

Abstract: The new natural fabric Grewia tiliflia was extracted from its tree. This uniaxial fabric was analyzed by chemical, Fourier transform infrared spectroscopy, thermogravimetric analysis, X-ray diffraction, scanning electron microscopy and polarized optical micro-scopic techniques. The effect of alkali treatment on the mechanical, morphological, and thermal properties of the fabric was examined. The tensile strength, modulus, and the thermal stability of the fabric were found to improve on alkali treatment. From the mechanical and thermal degradation studies of this fabric, it was concluded that the fabric can be used as reinforcement in the preparation of green composites and for other high-value fabric applications. [Copyright &y& Elsevier]

Abstract: Curaua fibres have specific mechanical properties similar to inorganic fibres and are an important renewable raw material. Milled curaua fibres, submitted to different treatments, were characterized by mechanical and thermal properties, moisture content, water absorption, surface morphology, FTIR spectroscopy, density and X-ray diffraction. Except for moisture content and mechanical properties, no other significant changes were observed after the treatments. The treated fibres also show an increase of surface roughness. [Copyright &y& Elsevier]

With respect to the fact that persimmon leaves having better effects on medical area applications, a persimmon leaves/cellulose blend fiber was prepared by wet spinning from a DMSO/polyoxymethylene solvent under different spinning conditions, e.g. the temperature of coagulation bath, amount of persimmon leaves added and concentration of spinning solution. Based on mechanical measurement, X-ray diffraction and DSC characterization, it was found that this blend fiber had similar mechanical and thermal properties as referenced cellulose fiber obtained using the same method. [Copyright &y& Elsevier]

• A novel core-shell starch-based nanoparticle (CSS NP) was prepared. • The compatibility of PPC/PLA was greatly improved by CSS NPs. • The mechanical properties of PPC/PLA/CSS were increased significantly. • The heat deformation temperature of PPC/PLA/CSS was improved remarkably. A novel core-shell starch-based nanoparticles (CSS NPs) with a "hard" starch core and a "soft" poly (methyl acrylate) (PMA) shell was prepared and incorporated into a PPC/PLA blend. The excellent compatibilization of CSS NPs was revealed by atomic force microscope (AFM), differential scanning calorimetry (DSC) and rheological test. More importantly, due to the excellent compatibilization the resulted PPC/PLA/CSS blend exhibited a strikingly improved mechanical and thermal properties. Compared to PPC/PLA (60/40), the elongation at break of PPC/PLA/CSS (60/40/20) increased greatly from 15 % to 272 % without sacrificing the tensile strength. Besides, the heat distortion temperature (HDT) of PPC/PLA/CSS (60/40/20) was improved to 47.3 °C, which was 20.5 °C higher than that of the neat PPC. These results established a novel and efficient strategy to improve the compatibility of polymer blends and to prepare polymer blends with balanced toughness and stiffness. [ABSTRACT FROM AUTHOR]

• Effect of CNF, and nanoclays (MMT and OMMT)) on the performance of kenaf/epoxy composites were investigated. • Incorporation of OMMT and CNFs enhanced the mechanical and thermal performance compared to MMT/kenaf/epoxy composites. • The obtained results revealed that OMMT and CNFs hybrid nanocomposites can be an efficient alternative for structural applications. The aim of the present research work has focused on investigating the effect of cellulose nanofibers (CNFs) and nano clays (montmorillonite (MMT) & organoclay (OMMT)) at 0.75Wt % on the performance of kenaf/epoxy composites. Mechanical (tensile and flexural) and thermal properties of composites in terms of morphology, thermal stability, weight loss, and dynamic mechanical properties were analyzed. The obtained results revealed that the integration of stiff CNFs as filler enhanced the mechanical and thermal properties, storage and loss modulus while a considerable decrease in Tan δ was realized compared to kenaf/epoxy composites. Enhancement in the properties was observed for OMMT and CNFs composites compared to MMT/kenaf/epoxy composites, which is attributed to the uniform filler distribution and interfacial adhesion between CNFs, OMMT, kenaf and epoxy matrix. The obtained results revealed that OMMT and CNFs based kenaf/epoxy composites can be an efficient alternative for construction applications. [ABSTRACT FROM AUTHOR]

• The cellulose is used as reactive filler in the synthesis of polyurethane foams. • The cellulose is used to tune the chemico-physical and mechanical properties of foams. • Two topologies of cellulose were used: crystalline and amorphous. • A reduction of the thermal conductivity of 33% is obtained with amorphous cellulose. • The amorphous cellulose modifies the mechanical behavior from rigid to semi-rigid. Cystalline-Cc and ultra-milled Amorphous-Ca cellulose were used as reactive filler to tune the performances of composite polyurethane-cellulose-foams, PUC. The effect of Cc and Ca on chemo-physical and mechanical properties of PUC was analysed through FTIR, morphological analysis, thermal conductivity and compression measurements. FTIR results show that, both Cc and Ca react with isocyanate through the OH functional groups contributing to the formation of a tough cellulose-polyurethane network. Morphological observations show that the addition of both Cc and Ca induces a decrease of average cell-size compared to the pristine-PU, thus confirming that they act as nucleating agent. In addition, the better dispersion of the Ca in the polyol, with respect to Cc induces, a finer cell leading to a reduction of the thermal conductivity around 33 % (for the composite loaded with 20 %wt-Ca) with respect to pristine-PU. Finally, the addition of Ca highly reactive modifies the mechanical behaviour from rigid-brittle to semi-rigid. [ABSTRACT FROM AUTHOR]