A molecular cobalt phthalocyanine (CoPc) catalyst has been integrated in an ethylene-bridged periodic mesoporous organosilica (PMO) to fabricate a hybrid material, CoPc-PMO, that catalyses CO2 reduction to CO in a photocatalytic system using [Ru(bpy)3]2+ (bpy = 2,2'-bipyridine) as a photosensitizer and 1,3-dimethyl-2-phenyl-2,3-dihydro-1H-benzo[d]imidazole (BIH) as an electron donor. CoPc-PMO displays a Co-based turnover number (TONCO) of >6000 for CO evolution with >70% CO-selectivity after 4 h irradiation with UV-filtered simulated solar light, and a quantum yield of 1.95% at 467 nm towards CO. This system demonstrates a benchmark TONCO for immobilised CoPc-based catalysts towards visible light-driven CO2 reduction.

In this study, formaldehyde-free bioresin adhesives were synthesised from lignin and tannin, which were obtained from softwood bark. The extraction was done via organosolv treatment and hot water extraction, respectively. A non-volatile, non-toxic aldehyde, glyoxal, was used as a substitute for formaldehyde in order to modify the chemical structure of both the lignin and tannin. The glyoxal modification reaction was confirmed by ATR–FTIR spectroscopy. Three different resin formulations were prepared using modified lignin along with the modified tannin. The thermal properties of the modified lignin, tannin, and the bioresins were assessed by DSC and TGA. When the bioresins were cured at a high temperature (200 °C) by compression moulding, they exhibited higher thermal stability as well as an enhanced degree of cross-linking compared to the low temperature-cured bioresins. The thermal properties of the resins were strongly affected by the compositions of the resins as well as the curing temperatures.

The fabrication of smart biocomposites from sustainable resources that could replace today's petroleum-derived polymer materials is a growing field of research. Here, we report preparation of novel biocomposites using nanocellulose networks extracted from food residue (onion skin) and a vegetable oil-based bioresin. The resin was synthesized via the Diels-Alder reaction between furfuryl methacrylate and tung oil at various ratios of the components. The onion-skin-extracted cellulose nanofiber and cellulose nanocrystal networks were then impregnated with the resins yielding biocomposites that exhibited improved mechanical strength and higher storage modulus values. The properties of the resins, as well as biocomposites, were affected by the resin compositions. A 190-240-fold increase in mechanical strength was observed in the cellulose nanofiber (CNF) and cellulose nanocrystal (CNC)-reinforced biocomposites with low furfuryl methacrylate content. The biocomposites exhibited interesting shape-memory behavior with 80-96% shape recovery being observed after 7 creep cycles.

This work focuses on the development of cross-linked polymer from a highly unsaturated vegetable oil, tung oil (TO) and a bio-based acrylate, furfuryl methacrylate (FMA). The presence of a high degree of unsaturated carbon-carbon bonding in TO makes it a suitable precursor for polymer synthesis. Using this advantage of TO, in this work, we have synthesised a cross-linked polymer from TO and FMA through free radical polymerisation followed by Diels–Alder (DA) reaction. Successful incorporation of both of the raw materials and the two chemical reactions was shown using Fourier-transform infrared (FTIR) and Raman spectroscopy. The development of cross-linked structure was analysed through thermogravimetric analysis (TGA) and dynamic mechanical analysis (DMA).

In recent years there has been a growing interest on biobased composites due to increased environmental awareness. Thermosetting bioresins are potential alternatives to synthetic ones to develop various composite products. This chapter covers the general introduction of bioresins and highlights the importance of biocomposites to meet the environmental challenges. Biocomposites specially produced from biobased thermosetting resins are discussed here. Thermosetting bioresins are interesting materials for developing highly cross-linked structures. A comparative study is done between the commercial grades of bioresins and bioresins synthesized in laboratories. The synthesis of thermosetting bioresins and their advantages and disadvantages are discussed here and finally, future prospects are analysed.

A simple method for preparing redispersible nanofibers from sugar beet residue and their use as a well-dispersed reinforcement for a polyvinyl alcohol (PVA) matrix is reported. It is known that the redispersion of dried cellulose nanofibers is difficult because of the formation of strong hydrogen bonds between the nanofibers. The results show that the properties of the initial sugar beet nanofiber suspension can be recovered without the use of chemical modification or additives with higher pectin and hemicellulose content. Undried and redispersed nanofibers with and without pectin were used as nanocomposite reinforcement with PVA. The redispersed nanofibers were as good reinforcements as the undried nanofibers. The tensile strength and elastic modulus of the nanocomposites with the redispersed sugar beet nanofibers were as good as those of the nanocomposites with undried nanofibers. Interestingly, the nanofiber dispersion in the PVA matrix was better when sugar beet nanofibers containing pectin and hemicellulose were used as reinforcements.

Acrylics and polyolefins are widely used synthetic plastics in daily consumer products which are non-biodegradable in nature. An accumulation of these solid wastes in the environment poses ecological threats and requires novel management techniques. Researchers have now focussed their work on developing novel biodegradable polymer materials and isolating and identifying microorganisms which have the potential to degrade these polymeric materials. Isolating and identifying these microorganisms having potential to degrade polymers and polymer composites are required for developing newer biotechnological techniques for management of these solid wastes in the environment. The present work studies the biodegradation behaviour of PMMA and micro-/nano-cellulose-reinforced PMMA (polymethyl methacrylate) composites in pond water. The weight loss data revealed improved biodegradability in cellulose-reinforced PMMA composites in comparison to the synthetic PMMA. Scanning electron microscopy (SEM) images revealed effective biodegradability of the composites in pond water. The microorganism (fungus) was isolated, and its biodegradation behaviour was studied.

The current work reports a novel, completely water based approach to prepare the water resistant modified cellulose nanopapers. Lactic acid in aqueous medium was attached on cellulose nanofibers surface with the aid of ultra-sonication and later oligomerized (polymerized) by compression molding under high temperature and pressure, to obtain the modified nanopapers with enhanced mechanical properties. The modified nanopapers showed an increase of 32% in the elastic modulus and 30% in the yield strength over reference nanopapers. Additionally, the modified nanopaper was hydrophobic in nature and had superior storage modulus under moist conditions. The storage modulus of wet modified nanopaper was three times (2.4 GPa) compared to the reference nanopapers (0.8 GPa) after 1 h immersion in water. Finally, the thermal stability of the modified nanopaper was also higher than reference nanopaper. The material reported is 100% bio-based.

A major research thrust is now taking place on the generation of micro- and nanocellulose from various renewable resources for use as reinforcement in polymer matrix composites. Preparation of nanocellulose from natural resources can lead to the production of biocomposites in an economic way. To achieve uniform dispersion of the cellulosic fillers in polymers and to reduce their high moisture absorption tendency, an in-situ polymerization technique can be adopted. Cellulose fibers are oft en chemically modified or surface treated with suitable chemicals. An in-situ polymerization technique can exploit the best possible effects of chemical modification, which enables formation of a chemical linkage between the cellulosic filler and the polymer during the course of polymerization. Also, the properties of the composites are further enhanced, the composites tend to become more biodegradable in composting environment, becoming more environmentally friendly, and their moisture absorption tendency is significantly reduced

Nanocellulose has gained attention in recent times due to their light weight, high strength, stiffness, biodegradability and renewability. Natural fibres have been used as reinforcement in composites for past many years, but the use of nanocellulose as reinforcement in composites is relatively new. The main challenges of preparing nanocellulose based composites include (i) generation of nanocellulose from natural resources, (ii) production in larger scale, (iii) enhancing compatibility with hydrophobic polymers, and (iv) achieving uniform dispersion in polymer matrices. These challenges have encouraged researchers to innovate efficient processes and techniques to utilise the maximum benefit of such green nanoscopic materials. In situ fabrication of cellulose nanocomposites is one such technique of achieving uniform nanocellulose dispersion in polymer matrices and obtaining a stronger filler/matrix interface. This review summarises the recent progress in the field of in situ processing of cellulose nanocomposites.

This article evaluates the role of cellulosic fillers in a synthetic polymer matrix like polymethylmethacrylate (PMMA) when incorporated by in situ suspension polymerization technique. Cellulose micro/nanofibers (CNF) were extracted from jute fibers and chemically modified with maleic anhydride (MACNF) to increase their interfacial compatibility with PMMA by participation of the MA moiety in the free radical polymerization with MMA. The effect of incorporating MACNF on the physical and mechanical properties of the PMMA matrix was investigated. Optical transparency was retained in the in situ prepared PMMA/cellulose composites (IPMC) similar to that of unreinforced PMMA. Another set of PMMA/cellulose composites was prepared by dispersing MACNF in PMMA matrix by ex situ solution dispersion method (EPMC). The modification of CNF with MA significantly improved the filler/matrix interfacial compatibility and in situ polymerization technique further enhanced the properties of the composites. The high moisture absorption tendency, which is a major drawback of the cellulose filled composites, remarkably reduced in IPMC. POLYM. COMPOS., 36:1748–1758, 2015. © 2014 Society of Plastics Engineers

Synthetic plastics like polyolefins, acrylics which are widely used in consumer products are not biodegraded by microorganisms in the environment. The accumulation of plastics in the environment becomes a matter of great concern leading to long-term environment, economic and waste management problems. In order to overcome these problems, significant attention has been given on biodegradable polymers, and also, on the identification of microorganisms with degrading potential upon polymeric materials. Therefore, recycling and biodegradation of these polymers is an important issue for environmental protection. The present work evaluates the effect of Maleic anhydride (MA) and Methylmethacrylate (MMA) modified cellulose micro and nano fibres (MACF and MMCF respectively) on the biodegradation behaviour of Polymethylmethacrylate (PMMA)/cellulose composites. MA and MMA modified cellulose reinforced PMMA composite granules were prepared by in-situ suspension polymerization technique. PMMA/cellulose composite films were prepared by solution casting method and the biodegradation behaviour of the films was studied by soil burial method in two types of soils (Soil A and Soil B). The biodegraded films were characterized by weight loss study, viscosity average molecular weights, scanning electron microscopy (SEM), differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR) and Nuclear magnetic resonance spectroscopy (NMR). The isolation and identification of the fungus, which degraded these composites, were done for the first time along with the biodegradation study with the isolated pure culture.

ABSTRACTCellulose micro/nanofibers (CNF), prepared from jute fibers were surface treated with methyl methacrylate (MMA) for better dispersion into poly methyl methacrylate (PMMA) matrix. PMMA/cellulose composites were prepared by in situ suspension polymerization technique. The surface treatment of CNF was confirmed by Fourier transform infrared spectroscopy (FTIR) and Nuclear magnetic resonance (NMR) analysis. MMA‐treated cellulose micro/nanofibers (MCNF) demonstrated improved affinity and dispersion in MMA monomer as well as in the PMMA/cellulose composites. Thermal properties of the cellulose composites were analyzed by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The glass transition temperature (Tg) of PMMA increased by nearly 19°C in the in situ cellulose composites compared to that of unreinforced PMMA as indicated by DSC. TGA showed increased thermal stability of the cellulose composites. Enhanced tensile properties as well as significantly lower moisture uptake were observed in the in situ prepared PMMA/cellulose composites. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 39808.

Micro/nano crystalline (MCC) cellulose particles were prepared from jute fibre by acid hydrolysis route. PMMA/cellulose (MCC) nanocomposites were prepared by in-situ polymerisation technique (IPC) and ex-situ dispersion technique (EPC). Biodegradation studies of IPC and EPC films were performed in a simulated aerobic compost environment for 60 days. IPC showed higher weight loss compared to that of EPC and unreinforced PMMA. The change in the molecular weights of PMMA in the biodegraded samples was determined by Gel Permeation Chromatography (GPC). The chemical structures of the biodegraded samples were examined with Nuclear Magnetic Resonance (NMR) study which indicated a significant change in the chemical structure of IPC after biodegradation. The surface morphologies of the samples before and after biodegradation were observed with Scanning Electron Microscope (SEM). The thermal transitions of PMMA in the biodegraded samples were examined with Differential Scanning Calorimetry (DSC).

Polymethylmethacrylate/cellulose nanocomposites were prepared by in situ polymerization and ex situ dispersion techniques with 10 wt% loading of cellulose nanoparticles. Cellulose nanoparticles were prepared from jute fibers by acid hydrolysis. The suspension polymerization of methylmethacrylate was carried out in presence of cellulose nanoparticles, which were dispersed in water medium and in situ polymethylmethacrylate/cellulose nanocomposite granules were formed. These granules were dissolved in chloroform, sonicated and films were prepared by solution casting method (IPC). Polymethylmethacrylate granules were prepared by similar suspension polymerization process and made into films by solution casting method. Another set of polymethylmethacrylate/cellulose nanocomposite films were prepared by dispersing nanocellulose powder (10 wt%) in polymethylmethacrylate solution and casting into films (EPC). The unreinforced polymethylmethacrylate and polymethylmethacrylate extracted from IPC films were subjected to size exclusion chromatography and nuclear magnetic resonance study. The average molecular weights of neat polymethylmethacrylate and polymethylmethacrylate from IPC were quite close, but the ‘dispersity’ was slightly higher in IPC than that in neat polymethylmethacrylate. Fourier transform infrared spectroscopy revealed some shifts in EPC. X-ray diffraction study showed a similar nature of X-ray diffraction curves in all the samples. Transmission electron microscopy of IPC and EPC showed a better dispersion of fillers and formation of a network structure in IPC, whereas in EPC, the fillers were agglomerated. Surface morphology of the films was examined by field emission scanning electron microscopy and atomic force microscopy. IPC exhibited a much smoother surface compared to that of EPC indicating a more homogeneous dispersion of fillers. IPC showed a higher modulus of elasticity compared to PMMA and EPC. Differential scanning calorimetry showed a shift of glass transition temperature to a higher one (125°C) in IPC compared to that of polymethylmethacrylate (118°C). Thermogravimetric analysis was done to study the thermal degradation behavior of the composites.

Two industrial wastes fly ash and polypropylene was used to develop novel composite materials. The fly ash (FA) particles were coated with stearic acid (SA) and palmitic acid (PA) in 1 wt% concentration. The surface coated fly ash particles were incorporated as filler in recycled polypropylene (RPP) matrix composites by melt mixing in 1:1 weight ratio. The composites were tested for their flexural properties, impact behaviour, dynamic mechanical properties and fracture surface analysis. Increase in flexural strength, modulus and impact strength was observed in the coated FA/RPP composites. 1 wt % PA coated FA/RPP composites showed great increase in flexural strength. In 1 wt% SA treated FA/RPP (RFASA1) composites highest shift in glass transition to a higher temperature were found. Fracture surface analysis revealed efficient filler matrix interactions in the SA and PA treated FA/RPP composites. Thus, green, renewable, inexpensive chemicals like stearic and palmitic acid was found to be an effective coupling agent in FA/RPP composites.

Recently, the polymeric composites from renewable resources have attracted great interest. The trend to develop novel eco-friendly green materials from various renewable resources leads to the full or partial replacement of synthetic materials towards a sustainable world also. With a high modulus of elasticity, low density, low production cost and energy consumption, easy processability, renewable nature and recyclability, cellulose nanoparticles have attracted considerable attention as reinforcing filler in polymer matrix composites for exploring new applications. Polymethylmethacrylate (PMMA)/cellulose nanocomposite films were prepared by in-situ polymerization with 10 weight% loading of cellulose nanofibers (CNF) and chemically modified cellulose nanofibers with maleic anhydride (M1CNF) and MMA (M2CNF) respectively to increase their interfacial compatibility with PMMA. The presence of the nanofiller increased the thermal stability of the nanocomposites, as measured by thermogravimetric analysis (TGA) and their glass transition temperature, measured by differential scanning calorimetry (DSC), as well as their average molecular weight measured by viscometric method. Mechanical test results showed that surface treatment of cellulose nanofibers significantly improved the tensile properties of PMMA nanocomposites. Biodegradation study was performed with soil burial method to analyze the effect of cellulose nanofibers on biodegradation.

Cellulose nanoparticles (CNPs) were prepared from jute fiber by acid hydrolysis followed by high-speed homogenization. The CNPs were used as fillers in the production of polymethylmethacrylate (PMMA) nanocomposites by in situ suspension polymerization technique. The suspension polymerization of MMA was carried out in the presence of CNPs, which were dispersed in water medium and in situ PMMA/cellulose nanocomposite granules were formed. PMMA polymer, without any filler, was also prepared by similar suspension polymerization technique. PMMA and PMMA/cellulose nanocomposite films were prepared by solution casting method. Viscosity average molecular weights of neat PMMA and the PMMA extracted from PMMA/cellulose nanocomposite granules were determined by viscometric method and average molecular mass of PMMA extracted from PMMA/cellulose nanocomposites was found to be reduced than that of neat PMMA. Attenuated total reflectance Fourier transform infrared spectroscopy was performed to find out any chemical interaction between polymer matrix and the CNPs. X-ray diffraction study and differential scanning calorimetry were done to investigate the structures of the nanocomposite films and the glass transition temperature was found to be lower in the nanocomposite than that in the virgin polymer. Field emission scanning electron microscopy and atomic force microscopy were done to examine the morphology of the films. Such an in situ suspension polymerization technique for the preparation of PMMA/cellulose nanocomposites can be very useful to prepare tailor-made materials. (c) 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012