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Design and manufacture of cellulosic nanocomposites with acceptable performance is in the period of a transition from fantasy to reality. Typically, cellulosic nanofillers reveal poor compatibility with polymer matrices. Thus, adjusting the balance between structure and properties of cellulosic bionanocomposites by careful selection of parent ingredients is the first priority. Herein, we incorporated Cuscuta reflexa derived cellulose nanofibers (CNFs) into acrylonitrile-butadiene rubber (NBR) for high-performance elastomeric applications. Tensile and tear strength of NBR improved by ~ 125 and ~ 105 %, respectively at a very low loading of 4 phr CNFs, as a result of interfacial bonding, as evidenced by fractographic analysis. In parallel, the temperature at which maximum degradation occurs (Tmax) of NBR rose by 14 °C. The swelling index and molar uptake of toluene were also lowered. The Wolff-activity coefficient, hardness, abrasion resistance, and cross-link density were all improved correspondingly. The positive shift in glass transition temperature and the fall in the loss tangent peak height for bionanocomposites proved the effective immobilization of NBR chains by well-dispersed CNFs. The hydrogen bonding interaction between –OH groups of CNFs and –CN groups of NBR might be responsible for the superior performance of NBR/CNF composites, which is confirmed by Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction analysis (XRD).

In the present work, we have developed a mesoporous silicalite-1 using CMC as a template for the removal of MB from aqueous solution. The synthesized silicalite-1 were characterized using scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), Energy-dispersive X-ray spectroscopy (EDAX) and N2 adsorption–desorption isotherm (BET). XRD and FT-IR analysis confirmed the formation of crystallinity and development of MFI structure in the mesoporous silicalite-1. The adsorption of MB dye on mesoporous silicalite-1 was conducted by batch adsorption method. The effect of various parameters such as adsorbent dosage, initial dye concentration, contact time and temperature on the dye uptake ability of silicalite-1 was investigated. The operating parameters for the maximum adsorption are silicalite-1 dosage (0.1 wt%), contact time (240 min), initial dye concentration (10 ppm) and temperature (30 ℃). The MB dye removal onto mesoporous silicalite-1 followed pseudo-second-order kinetic and Freundlich isotherm. The silicalite-1 exhibits 86% removal efficiency even after six adsorption–desorption cycle. Therefore, the developed mesoporous silicalite-1 is an effective eco-friendly adsorbent for MB dye removal from aqueous environment.

In the present work, we modified ZSM-5 zeolite using a bio polymer poly (diallyl dimethyl ammonium chloride) and employed it for the removal of cationic dye, methylene blue from aqueous solution. The chemical and physical properties of the modified ZSM-5 zeolite were investigated using XRD, FTIR, SEM, TEM, nitrogen adsorption, TGA and 27Al NMR. Modified ZSM-5 zeolite possesses high surface area and pore diameter which was confirmed from SEM, TEM and nitrogen adsorption analysis. Adsorption of methylene blue on zeolite was investigated by batch adsorption technique. The effect of different parameters such as zeolite dosage, initial methylene blue concentration, temperature, pH and contact time on the adsorption process was discussed. Maximum adsorption capacity (4.31 mg/g) was achieved using 0.1 g of modified ZSM-5 zeolite at the optimum conditions (initial dye concentration: 10 mg/L, pH 10, temperature: 30 °C and contact time: 300 min). The experimental data were fitted into Langmuir and Freundlich models and the results indicate that the adsorption process followed Freundlich isotherm. Kinetic data were investigated using pseudo-first-order and pseudo-second-order models. Kinetic analysis indicates that pseudo-second-order model is more suitable to describe adsorption of MB on modified ZSM-5 zeolite. The reusability test suggests that the adsorbent could be reused at least six times without significant loss in removal efficiency.

In this work, we examined ZSM-5 zeolite loaded polyvinyl alcohol-carboxymethyl cellulose-sodium alginate (PVA/CMC/SA) membrane for cationic dye (malachite green, MG) removal from aqueous environment. The crystallinity, chemical composition, surface morphology, hydrophilicity and thermal property of PVA/CMC/SA/ZSM-5 membrane was evaluated using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), optical microscopy (OM), contact angle and thermogravimetric analysis (TGA) respectively. The successful incorporation of zeolite into PVA/CMC/SA membrane was confirmed by XRD, FT IR and SEM. TGA and contact angle measurement indicates that zeolite loaded PVA/CMC/SA membrane showed superior thermal stability and hydrophobicity than plain PVA/CMC/SA membrane. A series of adsorption studies was conducted to evaluate the influence of operational parameters such as initial dye concentration, zeolite dosage, contact time, temperature and pH on the dye (MG) adsorption behaviour of the prepared membrane. A maximum dye removal percentage (99.12%) was achieved at an initial dye concentration of 10 ppm, zeolite dosage-5 wt%, pH = 10 and temperature-25 °C. The kinetic studies revealed that adsorption of MG on PVA/CMC/SA/ZSM-5 membrane follows pseudo-second-order model while Freundlich isotherm model was founded to be the best isotherm model to describe the adsorption process. The results thus indicate a multilayer adsorption of MG on PVA/CMC/SA/ZSM-5 membrane. Finally, the recyclability test revealed that the membrane exhibits good recycle efficiency and is stable after 5 recycle.

The use of chicken feather short fiber (CFF) as filler for polymer offers an ecofriendly method for the development of composites and coatings. In the present study, CFF filled epoxy coating has been developed to protect carbon steel from corrosion. The morphology of the coating surfaces was investigated using optical microscopy (OM) and atomic force microscopy (AFM). The surface properties such as wettability and surface roughness were determined. The corrosion studies on the coatings were evaluated using an accelerated salt immersion test. This green approach for the development of epoxy/CFF coating offers protection of metal parts used in many modern industries from the corrosive environment, improve the performance and ensure safety.

The biocomposites were produced by layering sequence of pure sisal fiber mat (SSSS), pure hemp fiber mat (HHHH), and their hybrid mats and then subjected to accelerated weathering conditions. The composite specimens were conditioned under ultraviolet (UV) light and water spray simultaneously for 2222 h, which corresponds to approximately 1 year of the outdoor conditions. Mechanical properties and thermogravimetric analysis (TGA) of the weathered composites were compared to the dry or unweathered composites. Chemical changes to the bio-based epoxy matrix and natural fiber induced by photodegradation were evident as a reduction in intensity and broadening of characteristic peaks from the Fourier Transform Infrared spectroscopy (FTIR) analysis. Tensile strength and flexural strength of the weathered HSSH and HSHS declined by 7%, 13%, 25%, and 26%, respectively. Degradation effects of weathering were also visible from the lower residue of the weathered composite specimens from the thermogravimetric analysis. Despite the slight drop in impact strength, all the weathered composite specimens had good impact resistance. Furthermore, the hybrid composites exposed to weathering had nearly equivalent impact strength compared to the pure sisal and hemp-based composites under the impact load. Based on this observation, sisal/hemp fiber bio-epoxy based hybrid composites are recommended for the outdoor structural applications requiring impact resistance.

In this work, the influence of weathering on the creep behavior of the sisal (SSSS), hemp (HHHH), and their hybrid composites (HSSH, and HSHS) was investigated. Composites were exposed to accelerated weathering for 2222 h, which replicates conditions equivalent to 1 year of outdoor exposure. Bio-epoxy based composites were fabricated by the hot press technique. Creep study was performed in a dynamic mechanical analyzer under the dual cantilever creep mode at 30 °C and 50 °C testing temperature under a load of 5 N. The creep-recovery behavior of the weathered composite specimens was evaluated and compared with the unweathered specimens. The investigation revealed that creep strain decreased with the incorporation of the sisal and hemp fibres into the bio-epoxy matrix. The experimental creep response of the composites was also in good agreement with the analytical results from Burger’s model. Both the weathering and testing conditions at elevated temperature (50 °C) had a significant impact on the creep resistance of the composites. The creep resistance of the hybrid composites was found to be dependent on the layering sequence. HSHS configuration almost displayed similar creep properties before and after weathering. HSSH configuration was found to have lower creep resistance after weathering. Scanning electron microscopy was used out to examine the fibre-matrix interface of the composites.

In this study, a novel PVA/SA/ZSM-5 zeolite membrane with good regeneration capacity was successfully prepared by solvent casting technique. The properties of the membranes were assessed by employing different characterization techniques such as X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), scanning electron microscope (SEM), optical microscopy (OP), thermogravimetric analysis (TGA), contact angle and universal testing machine (UTM). XRD, TGA and UTM results revealed that the crystallinity and thermo-mechanical performance of the membrane could be tuned with zeolite content. The successful incorporation of zeolite into the polymer matrix was confirmed by FT-IR, SEM and OP analysis. The adsorption ability of the as-prepared membrane was evaluated with a model anionic dye, Congo red. Adsorption studies show that the removal efficiency of the membrane could be tuned by varying zeolite content, initial concentration of dye, contact time, pH and temperature. Maximum dye adsorption (5.33 mg/g) was observed for 2.5 wt% zeolite loaded membrane, at an initial dye concentration of 10 ppm, pH 3 and temperature 30 °C. The antibacterial efficiency of the membrane against gram-positive (Staphylococcus aureus) and gram-negative bacteria (Escherichia coli) was also reported. The results show that membrane inhibits the growth of both gram-positive and gram-negative bacteria. The adsorption isotherm was studied using two models: Langmuir and Freundlich isotherm. The results show that the experimental data fitted well with Freundlich isotherm with a high correlation coefficient (R2 = 0.998). Meanwhile, the kinetic studies demonstrate that pseudo-second-order (R2 = 0.999) model describe the adsorption of Congo red onto PVA/SA/ZSM-5 zeolite membrane better than pseudo-first-order (R2 = 0.972) and intra particle diffusion model (R2 = 0.91). The experimental studies thus suggest that PVA/SA/ZSM-5 zeolite could be a promising candidate for the removal of Congo red from aqueous solution.

Here we investigated the application of a novel polyvinyl alcohol/starch/ZSM-5 zeolite membrane as an adsorbent for the removal of Eriochrome black T (EBT) from aqueous medium. Physical and chemical structure of the membranes was characterized by scanning electron microscopy, optical microscopy, Fourier-transform infrared spectroscopy, X-Ray diffraction, thermogravimetric analysis and universal testing machine. Swelling measurement shows that with increase in zeolite content the hydrophobicity of the membrane also increases. Adsorption measurements were monitored spectrophotometrically at 530 nm. Results indicate that the operational parameters (initial dye concentration, zeolite dosage, temperature, pH and contact time) has significant influence on the adsorption behavior of the membrane. The maximum adsorption capacity was estimated to be 2.17 mg/g for 5 wt% zeolite loaded membrane at an initial concentration of 10 mg/L, at room temperature and at pH 3. Adsorption kinetics analysis revealed that pseudo-second-order model describes the adsorption of EBT onto PVA/starch/ZSM-5 zeolite membrane with correlation coefficient close to one. Adsorption isotherm was analyzed using Langmuir and Freundlich isotherm models and the result shows that adsorption follow Freundlich isotherm model. Adsorption–desorption studies suggests that the membrane possess good regeneration capacity.

The viscoelastic effects during reaction induced phase separation play an important role in toughening epoxy-based blends. The large difference in molecular weight/glass transition temperature between the blend components before the curing reaction results in dynamic asymmetry, causing viscoelastic effects during phase separation accompanying the curing reaction. This review will focus on the key factors responsible for viscoelastic phase separation in epoxy-based blends and hybrid nanocomposites. Time-resolved characterization techniques such as rheometry, small angle laser light scattering, optical microscopy etc., are mainly used for monitoring the viscoelastic effects during phase separation. Incorporation of nanofillers in epoxy thermoplastic blends enhances the viscoelastic phase separation due to the increase in dynamic asymmetry. Different theoretical models are identified for the determination of processing parameters such as temperature, viscosity, phase domain size, and other parameters during the viscoelastic phase separation process. The effect of viscoelastic phase separation has a very strong influence on the domain parameters of the blends and thereby on the ultimate properties and applications.

In this work, graphene was used as a filler for banyan aerial root fibers reinforced epoxy composites at various compositions. The synergetic effect of graphene and banyan fibers, on the physical a...

We report the synthesis of giant carbon particles with spherical and interconnected porous morphologies. Direct organic–organic self-assembly between phenolic resin and polystyrene-block-poly(ethylene oxide) (PS-b-PEO) was employed to prepare these highly ordered carbon particles. Mesoporous carbon nanoparticles with tunable textural characteristics such as large surface area, uniform pore structure, and high thermal properties were achieved by simply adjusting the ratio between the block copolymer to phenol without using acid, base, or activating agents. The synthesized nanoparticles possess a very high surface area of up to 832 m2 g–1, and ultrasmall pore size, as small as 3 nm, and exhibited excellent electrochemical performance when used as active electrodes for lithium-ion batteries. Making use of the secondary interactions between the functional groups of the block copolymer and phenol, this study created tunable nanoparticles with excellent surface area and uniform morphologies that can be used in ...

Designing environmentally friendly materials from natural resources represents a great challenge in the last decade. However, the lack of fundamental knowledge in the processing of the raw materials to fabricate the composites structure is still a major challenge for potential applications. Natural fibers extracted from plants are receiving more attention from researchers, scientists and academics due to their use in polymer composites and also their environmentally friendly nature and sustainability. The natural fiber features depend on the preparation and processing of the fibers. Natural plant fibers are extracted either by mechanical retting, dew retting and/or water retting processes. The natural fibers characteristics could be improved by suitable chemicals and surface treatments. This survey proposes a detailed review of the different types of retting processes, chemical and surface treatments and characterization techniques for natural fibers. We summarize major findings from the literature and the treatment effects on the properties of the natural fibers are being highlighted.

In this work, we have developed super tough ternary polymer blends and composites composed of polystyrene (PS), low-density polyethylene (LDPE), polystyrene-block-poly(ethylene-ran-butylene)-block-polystyrene (SEBS) and exfoliated graphene nanoplatelets (xGnP). A 50/50 composition of PS and LDPE was selected for making the binary blend. The addition of xGnP in the binary blend reduces the tensile strength, elongation at break and tensile toughness considerably due to the unfavorable interactions existing between PS, LDPE, and xGnP. On the other hand, the mechanical properties of PS/LDPE binary blends are considerably improved by the addition of SEBS at the expense of modulus. The best results were obtained for a 33/33/33 (PS/LDPE/SEBS) composition. Further, different concentrations of xGnP were incorporated in the ternary blend with 33/33/33 composition. Interestingly, the composites show a significant improvement in mechanical properties especially for 2.91 wt% xGnP modified ternary blend. The DMA studies revealed that the stress with in the ternary composites are minimum when compared with binary blends and their composites. The variation in the phase morphology of the binary blends by the addition of SEBS and xGnP is responsible for the dramatic changes in mechanical and viscoelastic properties. This study validates large improvement in mechanical properties of the PS/LDPE polymer blends by the careful selection of SEBS and xGnP. Keywords: Polystyrene, Low-density polyethylene, Polystyrene-block-poly(ethylene-ran-butylene)-block-polystyrene, Exfoliated graphene nanoplatelets, Toughened plastics

The aim of this study is to investigate natural cellulosic fibers extracted from Tridax procumbens plants. The obtained fibers were alkali treated for their effective usage as reinforcement in composites. The physical, chemical, crystallinity, thermal, wettability and surface characteristics were analyzed for raw, and alkali treated Tridax procumbens fibers (TPFs). The test results conclude that there was an increase in cellulose content with a reduction in hemicellulose, lignin, and wax upon alkali treatment. This enhanced the thermal stability, tensile strength, crystallinity, and surface roughness characteristics. The contact angle was also lesser for treated TPFs which prove its better wettability with the liquid phase. The Weibull distribution analysis was adopted for the analysis of the fiber diameter and tensile properties. Thus the considerable improvement in the properties of alkali treated TPFs would be worth for developing high-performance polymer composites.

A cheap and eco-friendly polyvinyl alcohol (PVA)/chitosan (CS)/honey membrane was successfully developed using solvent casting technique. The prepared membranes were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), atomic force microscopy (AFM), thermogravimetric analysis (TGA), contact angle, optical microscopy (OM) and universal testing machine (UTM) analysis. XRD results indicate that the membrane is crystalline, while FT-IR data confirm the successful incorporation of honey into the PVA/chitosan membrane. SEM analysis revealed that the surface morphology of the PVA/CS membrane is intact even after the incorporation of honey, which is corroborated by AFM and optical microscopic analysis. Contact angle measurement suggests that the hydrophilicity of the membrane increases with honey concentration. The membrane possesses good thermal and mechanical stability as indicated by TGA and UTM analysis. Disc diffusion method was employed to investigate the antibacterial activity of the membrane and the result shows that the membrane possesses good antibacterial activity against Staphylococcus aureus (Gram-positive bacteria) and Escherichia coli (Gram-negative bacteria). The antibacterial activity of the membrane could be tuned by honey concentration and 15 wt% honey loaded membrane displayed highest zone of inhibition (diameter: 8 mm (E. coli) and 14 mm (S. aureus). Our studies thus suggest that the PVA/chitosan/honey membrane could be a potential candidate for wound dressing applications.

It is a major challenge to reduce water diffusion through hydrophilic polymers like epoxies without affecting their thermomechanical performance. Herein, both graphene oxide (GO) nanosheets and barium oxide (BaO) microparticles were incorporated together into epoxy to develop water resistant epoxy/BaO/GO nanocomposite. The manuscript signifies the role of these fillers in reducing water diffusion through epoxy matrix without deterioration in its basic thermal and mechanical properties. Morphological studies of epoxy/BaO/GO nanocomposites revealed the presence of uniformly distributed micro/nano-clusters of graphene oxide sheets and BaO. This enhanced the hydrophobicity of the nanocomposite with a water contact angle of 131.7°. The BaO/GO micro/nano-clusters also created a barrier to the diffusion of water molecules which reflected in the lower diffusion coefficient of epoxy/BaO/GO nanocomposite. Dynamic mechanical analysis (DMA), thermogravimetric analysis (TGA), and thermomechanical (TMA) analysis has been carried out to investigate the viscoelastic, thermal stability, and dimensional stability of the prepared composites. Good viscoelastic performance of epoxy/BaO/GO nanocomposite with balanced thermal stability and dimensional stability has been confirmed. The developed water resistant epoxy nanocomposite is suitable to be used in areas where moisture attack is a serious concern.

Here the fabrication of a novel PVA/CMC/halloysite nanoclay membrane for the effective adsorption of cationic dye (methylene blue, MB) from aqueous environment is reported. The membranes were analyzed through scanning electron microscopy (SEM), optical microscopy (OM), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), contact angle and universal testing machine (UTM) analysis. The adsorption behavior of the membrane in terms of nanoclay loading, contact time, initial concentration of MB, pH and temperature were also discussed. The membrane exhibits excellent removal efficiency (99.5%) for MB in the optimal conditions such as nanoclay dose = 6 wt%, initial dye concentration = 10 ppm, contact time = 240 min, pH = 10 and temperature = 30 °C. Three isotherm models (Freundlich, Langmuir and Temkin) were employed to analyze the dye adsorption data. The results revealed that the adsorption process could be described well with both Freundlich and Langmuir isotherm model. The kinetics of MB adsorption onto membrane follows pseudo-second-order model while thermodynamic parameter indicate that adsorption is feasible and endothermic in nature. The antibacterial studies revealed that the PVA/CMC/halloysite nanoclay membrane possess notable antibacterial property. Finally, the desorption studies showed that the membrane have good reusability even after four recycles.

In a world that canopies numerous opportunities to advance towards a green sustainable life, biopolymer development offers a platform that fits into the paradigm of achieving an eco-friendly environment whilst reducing reliance on the scarce fossil fuel elements for the fabrication of day-to-day products. Today's technological improvements have aided biopolymer end-products to escalate to higher purposes and soon may have their performance level in par with the petroleum-based synthetic polymers. The motive of this paper is to shimmer light on some aspects of biopolymers that include its classes, properties, composites and applications. Depending on the type of class on the basis of various categories, many enthralling chemistries of polymer composition can be substantiated. Essential properties can imparted to the ensuing biopolymer by altering its chemical configuration and method of synthesis while also focusing on its functional purpose. Nowadays, biopolymer composites blend qualities of one biopolymer with another to acquire an enhanced component that showcases unique explicit attributes. There are several techniques to process biopolymer composites, of which in-situ, infiltration and electrospinning methods have captured considerable limelight. Biopolymers and its composites have embarked captivating impressions in regions of biomedical, packaging, agricultural and automotive applications. Although their efficacy is yet to reach their fossil fuel counterparts, biopolymers have laid a distinguishing mark that will continue to inspire creation of novel substances for many years to come.

Self-healing materials attract enormous scientific attention as they offer wide range of applications in conjunction with long-lasting performance. Self-healable polymers find potential candidates for construction materials, automotive parts, electrical encapsulation, adhesives, coatings, etc. Due to the lightweight, high thermo-mechanical performance, excellent adhesion, gloss, good chemical resistance, and corrosion resistance, epoxy resins are preferred over other polymers for coating applications. Although epoxy resin coatings are widely used in commercial vehicles and high compact aircraft, their susceptibility toward scratches and microcracks is a major concern. Such failures may be addressed by making use of self-healing epoxy coatings. In this review, we focus on inhibitor and polymeric healing agents encapsulated in organic and inorganic containers for the self-healing epoxy coating. The different organic and inorganic containers such as micro/nano polymer capsules, cellulose nanofibers, halloysite nanotubes, titanium dioxide nanocontainers, mesoporous silica, hollow glass fibers, and core–shell nanofibers have been utilized as reservoirs to store the self-healing agents. In addition, self-healing techniques such as layer-by-layer method, microvascular networks, ion exchange method, reversible crosslinks, and shape memory assisted self-healing are reviewed.

In this work, we prepared thermoresponsive shape memory epoxy thermosets by blending epoxy resin with poly(ethylene glycol-ran-propylene glycol) random copolymer (PEG-ran-PPG or RCP). Incorporation of RCP precisely tuned the temperature showing the shape memory effect of epoxy thermoset, which was established by dynamic mechanical analysis (DMA) and fold-deploy test. FTIR spectroscopy confirmed that the compatibility of the system is caused by intermolecular hydrogen bonding and only at high RCP concentration some phase separation starts. DMA and thermomechanical analysis provided evidence for the interactions of RCP chains with epoxy thermoset. The impact strength considerably increased especially for 30 and 40 wt % RCP modified blends. Furthermore, the blends exhibited good thermal stability in conjunction with excellent UV resistance.

In this paper, we report a simple method to prepare novel, transparent, hard-tough and hard-flexible shape memory and soft-flexible epoxy polymers based on poly(propylene glycol)-block-poly(ethylene glycol)-block-poly(propylene glycol) (PPO-PEO-PPO) triblock copolymer (TBCP) and diglycidyl ether of bisphenol-A (DGEBA)/4,4'-diaminodiphenylmethane (DDM) system. The PPO-PEO-PPO triblock copolymer was used to tailor crosslink density and flexibility in epoxy thermosets and thereby their glass transition temperature (Tg). The formed blends exhibit a phase separated morphology. The phase separation was initiated by immiscible PPO blocks via self-assembly. Three types of shape memory polymers, viz. stiff, intermediate and soft-flexible epoxy systems, with entirely different physical and mechanical properties were prepared only by adjusting the blend composition. All the blends were UV resistant, thermally and dimensionally stable and could be used for various outdoor applications. To the best of our knowledge, n...

The localization of organically modified nanoclays in chlorobutyl rubber (CIIR) and natural rubber (NR) blend system was carefully studied by following the vulcanization behaviour, morphology, thermal and solvent permeation characteristics. From the vulcanization studies, it was observed that incorporation of nanoclay platelets significantly affected the viscosity and vulcanization parameters such as cure time, scorch time, rate of cure and the degree of cure. Thermal analysis pointed out that the addition of nanoclay increased the thermal stability of the elastomer blends. The morphology of the blends indicated that the nanoclay platelets were localized at the interface and in both phases (mixed mode morphology) of elastomer blends and this affected the overall properties. The transport characteristics of NR/CIIR blend nanocomposites using toluene as the solvent were also studied. The transport parameters such as the equilibrium uptake, diffusion coefficient and the rate constant have been computed. The transport characteristics have been correlated with the microstructure of the blend nanocomposites. Finally, applied the Peppas–Sahlin model to fit the experimental diffusion data and the fitting was found to be reasonably good. POLYM. COMPOS., 2017. © 2017 Society of Plastics Engineers

A facile approach to prepare bionanocomposites of poly(butylene adipate-co-terephthalate) (PBAT) is reported in this paper. The effect of different wt% of hemp/Sihemp, carbon nanofiber (CNF) and silver nanoparticle (Ag-NPs) on the density, water absorption, melting and crystallization behavior, thermal stability, mechanical properties and morphology was investigated. The density of the composites was reduced except for Ag-NPs reinforced nanocomposites while diffusion coefficient and maximum water absorption were decreased for Sihemp reinforced composites making it a suitable material to replace conventional polymers. Significant improvement in tensile strength (TS) and tensile modulus (TM) was observed for the PBAT/Sihemp composites. For CNF and Ag-NPs reinforced nanocomposites, mechanical properties were retained at lower filler concentration. But as the concentration increased, there was a tendency for the nanofillers to agglomerate, which resulted in a reduction in mechanical properties.

In this paper, we report on the effect of amphiphilic poly(ethylene oxide)-poly(propylene oxide)poly(ethylene oxide) (PEO-PPO-PEO) triblock copolymer (TBCP) on the miscibility, phase separation, thermomechanical properties and surface hydrophobicity of diglycidyl ether of bisphenol-A (DGEBA)/4,4'-diaminodiphenylmethane (DDM) system. The blends were nanostructured. The phase separation occurred via self-assembly of PPO blocks followed by the reaction induced phase separation of PEO blocks. The surface roughness increased with increase in concentration of TBCP due to increased phase separation of PEO blocks at higher concentration. The phase separated PEO blocks formed the crystalline phase in the amorphous crosslinked epoxy matrix. The TBCP has a strong plasticizing effect on the matrix and decreased the glass transition temperature (T-g) and modulus of the thermoset. The incorporation of TBCP improved impact strength and tensile properties and 5 phr TBCP content was found to be optimum to achieve balanced mechanical performance. Moreover, the thermal stability of the epoxy system was retained while hydrophobicity was improved in the presence of TBCP. (C) 2017 Elsevier Ltd. All rights reserved.

Binary and ternary blends comprised of polypropylene (PP), polystyrene (PS) and polystyrene-block-poly(ethylene-ran-butylene)-block-polystyrene (SEBS) were prepared. The effect of phase composition of minor components on the morphology, mechanical, viscoelastic, crystallization, and thermal degradation properties was studied. Binary blends exhibited inferior properties, typical of immiscible and incompatible multi-phase systems and showed matrix-droplet phase morphologies. Ternary blends, especially those with greater concentration of SEBS minor phase, exhibited interesting properties. Scanning electron micrographs of SEBS compatibilized PP/PS blends, did not show any PS particle pulling out of the PP matrix, indicating good compatibility of SEBS with PP/PS blends. Dynamic mechanical analysis also supported the heterogeneous phase structure of the blends. Thermogravimetry and differential scanning calorimetry showed that addition of PS and SEBS decreased the thermal stability of PP marginally, but shows slight variations in melting and crystallization behavior.

The increase in awareness of the damage caused by synthetic materials on the environment has led to the development of eco-friendly materials. The researchers have shown a lot of interest in developing such materials which can replace the synthetic materials. As a result, there is an increase in demand for commercial use of the natural fiber-based composites in recent years for various industrial sectors. Natural fibers are sustainable materials which are easily available in nature and have advantages like low-cost, lightweight, renewability, biodegradability, and high specific properties. The sustainability of the natural fiber-based composite materials has led to upsurge its applications in various manufacturing sectors. In this paper, we have reviewed the different sources of natural fibers, their properties, modification of natural fibers, the effect of treatments on natural fibers, etc. We also summarize the major applications of natural fibers and their effective use as reinforcement for polymer composite materials.

The effect of recycling on the thermo-mechanical and water absorption behavior of polypropylene (PP)/sisal fiber and polylactic acid (PLA)/sisal fiber composites were studied. The PP-based non-biodegradable composites and PLA-based biodegradable composites were recycled for four times. The effect of recycling was determined by examining the morphology, thermo-mechanical properties, and water absorption behavior and the obtained results were compared. The results showed that the incorporation of sisal fibers in the PP and PLA matrix enhances the tensile modulus and percentage crystallinity of the composites. The tensile strength and modulus of the sisal fiber reinforced PP composites were not affected with recycling. Even though the tensile properties of PLA and PLA/sisal fiber reinforced composites are superior to PP and PP/sisal fiber composites, the PLA-based composites show a dramatic decrease in tensile strength and modulus after the first recycling due to the degradation of the polymer. The thermal stability of the PP/sisal fiber composites was not affected by the repeated recycling process. On the other hand, the PLA-based composites with higher sisal fiber content show a bit lower thermal stability after recycling. The PP-based composites show fluctuations in percentage crystallinity with recycling. On the other hand, a remarkable increase in percentage crystallinity for PLA and PLA-based composites was observed with increasing recycling times. Water diffusion study divulges that the diffusion of water into the polymer composites was reduced with recycling, irrespective of the polymer matrix.

Three-dimensional graphene architectures were synthesized from a new source, chicken feather, a bio-waste. Here ferric chloride (FeCl3) was used as a self-originator template, with a high C/O ratio (21:1). The introduction of Fe3＋ ion into the activated frame of carbon generated graphene nanostructure. X-ray photoelectron spectroscopy was used to analyse the defects in the prepared graphene. The obtained structures were found to be unique nanoplatelets and three-dimensional pyramid-like structure. Its DC conductivity has been tested within the temperature range of 20 to 300K and their temperature-dependent conduction mechanism was established. At ∼ 100 K and ∼ 50 K, a 3D–2D and Mott–ES type cross-over were observed respectively, with varied hopping length. The conductivity was found to be decreased with lowering temperature which was similarly observed in metals.

Zeolite are porous material with high surface area and adsorption capacity. It has been employed for the removal of organic contaminants from aqueous system. Here, we report the synthesis of mesoporous ZSM-5 zeolite using a bio template, cellulose. The adsorbent was investigated in detail by different characterization techniques such as Fourier transform infrared spectroscopy (FTIR), X‐ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), N2 adsorption, thermogravimetric analysis (TGA) and 27Al nuclear magnetic resonance (NMR) analysis. The crystalline and MFI nature of the mesoporous ZSM-5 zeolite was confirmed by XRD and FTIR analysis. N2 adsorption/desorption result showed that mesoporous ZSM-5 zeolite has high surface area and pore diameter which was later confirmed through morphological characterization such as SEM and TEM. The adsorption ability of the mesoporous ZSM-5 zeolite was evaluated using methyl orange (MO), an anionic azo dye. The effect of initial dye concentration, adsorbent amount, contact time, temperature and pH on the MO removal process was reviewed. The percentage removal of mesoporous ZSM-5 zeolite is 94.3 % which is much higher than that of the conventional ZSM-5 zeolite (73.2 %). Adsorption isotherm studies were interpreted using two different models i.e., Langmuir and Freundlich model. The result indicates that the adsorption could be well described by Freundlich isotherm model. Meanwhile, kinetic data were best described by pseudo-second-order model. The recyclability test suggest that the synthesized adsorbent has superior regeneration capacity and is stable even after eight adsorption-desorption cycle. Thus, our results show that mesoporous ZSM-5 zeolite is a promising competitor for the removal of dye from aqueous medium.

This review provides a comprehensive analysis of available peer-reviewed literature in which graphene and/or its derivatives are incorporated into a polymer matrix in order to enhance the final properties and functionalities of the three dimensional (3D) printed structure. Research in which graphene derivatives have been incorporated into plastic 3D printing technologies such as Fused deposition modeling (FDM), Stereolithography (SLA), Selective laser sintering, Inkjet 3D printing, Extrusion-based printing and Binder-jet printing is presented. For certain design requirements and applicability of the material, great care needs to be taken to select the appropriate printing method. Factors which play a key role in final performance of the printed parts are identified, including dispersion of graphene or its derivatives in matrix, interfacial interaction between graphene or its derivatives and matrix, printing orientation, nanofiller's aspect ratio, reduction of graphene oxide and ink viscosity. In fact, the multifunctional applications of the 3D printed structures based on graphene or graphitic filler composites open up the countless possibilities of current research. Although great progress has been made in exploring the mechanical, electrical, optical and thermal, characteristics of these materials, significant research and development need to be done to fully fetch their inherent potential. This article serves the purpose to researchers to improve latest research outcomes and explore new graphene–based nanocomposites for different applications.

Epoxy resin/4,4′-diaminodiphenylsulfone (DDS) system was modified by the incorporation of poly(e-caprolactone)-block-poly(dimethyl siloxane)-block-poly(e-caprolactone) (PCL–PDMS–PCL) triblock copolymer (TBCP). Morphology, viscoelasticity, thermo-mechanical and surface properties of these blends were investigated. All the blends were opaque after curing. PCL blocks of the TBCP were miscible with epoxy resin while the PDMS fraction was immiscible. However in the cured state, both PCL and PDMS blocks were phase separated from epoxy/DDS matrix. The blends exhibited matrix-droplet morphology in which TBCP phase dispersed as spherical domains in epoxy matrix. Addition of TBCP had profound impact on the cure reaction kinetics. Storage modulus and glass transition temperature (Tg) decreased while impact strength significantly increased. Incorporation of 15 phr of TBCP resulted in 80% improvement in impact strength. Further, thermal stability was unaffected while surface hydrophobicity of the blends increased.

Mechanical and physical properties of polypropylene (PP)/polystyrene (PS) blend, PP/PS/polystyrene-block-poly(ethylene-ran-butylene)-block-polystyrene (SEBS) ternary blend and their composites with carbon nanofibers (CNF) were investigated. Composites of ternary blend exhibited superior properties compared to those of binary blends. Mechanical performance of nanocomposites was intimately related to their phase morphology. PP/PS/SEBS/0.1 wt% CNF hybrid composites exhibited excellent impact strength (Four-fold increase compared to PP/PS blend) and ductility (12-fold increase in elongation at break, with respect to PP/PS blend). Moreover, these composites displayed good tensile strength and modulus (15% increase in Young's modulus, compared to PP/PS/SEBS blend) and are suitable for various end-use applications including automobile applications. Although crystallinity of PP phase is decreased by the incorporation of CNF, thermal stability of the composites remained almost unaffected. Contact angle measurements revealed that ternary composites exhibited maximum hydrophobicity.

For the first time, unique microsphere of ruthenium manganate was prepared by the sol-gel assisted xerogel sintering methodology. X-ray diffraction results showed that the materials were comprised of a distinctive tetragonal structure with a cell volume of 323 (A3). Ru4+ has successfully combined with the Mn2+ to form the compact lattices. The interatomic distances and angles of the three corresponding neighboring atoms were calculated with their preferred unit cell structure. SEM and TEM study confirmed the development of solid microsphere. Energy dispersive X-ray analysis showed elemental percentage on materials surface. X-ray photoelectron spectroscopy demonstrated the quantified oxidation states of the elements. Magnetic measurements performed in the temperature range of 10 K–300 K indicated that the sample showed predominantly superparamagnetic character at room temperature.

Carbon-based nanomaterials such as carbon nanotubes (CNTs) have become the most promising materials in biomedical, electronic and aerospace applications. When added to polymers, they can enhance the properties and the utility of the polymers to a large extent. This is because of their superior thermo-mechanical and electrical properties which can be effectively transferred to the resulting composites with their proper dispersion in the polymer matrix. But the uniform dispersion of CNTs in various polymer matrices is the major challenge faced by scientists. This paper critically reviews the different chemical strategies adopted for grafting polymers onto the CNTs which ultimately leads to better polymer-filler interaction and optimum filler dispersion for the development of high-performance polymer nanocomposites. This review also discusses the synthesis, properties, and applications of polymer grafted CNTs and their composites.

Nickel manganate nanorod (NNM) decorated reduced graphene oxide (NNMG) was developed and its structure-property correlations in light of X-ray diffraction (XRD), Raman, field emission-scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS) were evaluated. The starring role of NNM and reduced graphene oxide (RGO) in NNMG for CO sensing was explored and an insight into the mechanistic pathway of sensing was proposed. NNMG displayed an excellent response % (∼ 7000) and sensitivity (0.60 ppm−1), which can surpass most stable efficient sensors, indicative of the synergistic effect of RGO and NNM. Moreover, NNMG can competently sense CO gas at wide range of concentration (25–200 ppm) with good stability and reversibility. Ligand like approach of CO facilitated donation of electron to the lattice oxygen vacancy and subsequently decrease electron barrier at the Schottky junction, resulting the higher response. The obtained outcomes demonstrated that the rational design of nanorod decorated RGO could be a promising strategy to improve CO sensing performance.

The reduction of the environmental impact from renewable resources can provide an interesting sustainable platform. Natural fiber is an outstanding renewable resource for making composite materials for lightweight applications. However, the major disadvantage of natural fiber as reinforcement material in composites is their hydrophilic nature. The present investigation is an attempt to develop kenaf/sisal fiber fabric reinforced bioepoxy hybrid composites and assess the performance of the composites under accelerated weathering conditions. To the best of our knowledge as of now there is no work has been published in this concept. The bioepoxy resin and kenaf/sisal fiber fabrics were used for making hybrid bio-based composites and manufactured composite laminates using a compression molding method. For comparison purpose, a neat bioepoxy thermoset was fabricated by casting mold technique. To promote the accelerated weathering of composites, the samples were exposed to environmental conditions such as ultraviolet radiation, extreme temperature and humidity conditions in accelerated weathering tester machine according to ASTM G155-13 cycle 1. The tensile, impact, morphology, thermogravimetric analysis, dynamic mechanical analysis, and water absorption test were performed for both before and after weathering test samples according to international standards. The results indicated that the manufactured fully bio-based kenaf/sisal fiber reinforced hybrid bioepoxy composites showed moderate properties when compared to the neat bioepoxy composite at both before and after weathering conditions. From the results, it is worth to point out that these fully bio-based composites are promising composite material for semi-structural applications.

Epoxy resin was modified by the incorporation of poly (e-caprolactone)-block-poly (dimethyl siloxane)-block-poly (e-caprolactone) (PCL–PDMS–PCL) triblock copolymer (TBCP) in the presence of 4,4′-diaminodiphenylmethane (DDM). The role of intermolecular hydrogen bonding interaction in cure behavior, morphology, thermo-mechanical and surface wetting properties of TBCP modified epoxy thermoset was investigated. Fourier transform infrared (FTIR) spectroscopy, differential scanning calorimetry (DSC), atomic force microscopy (AFM), scanning electron microscopy (SEM), universal testing machine (UTM), thermogravimetric analysis (TGA) and contact angle measurements were used to characterize the samples. It is observed that PCL blocks of the TBCP were miscible with epoxy phase while the PDMS blocks remain immiscible. The miscibility of TBCP was analyzed and confirmed by FTIR and DSC, however, nanoscale inhomogeneities with ca. 20 nm were observed while examining AFM images. Addition of TBCP decreased the crosslink density between the polymers and therefore reduced the glass transition temperature (Tg), signifying the interpenetration of PCL blocks into the epoxy matrix. All the prepared blends showed shape memory effect. TBCP was very effective in improving the mechanical properties of epoxy matrix. Incorporation of 5 phr of TBCP improved the tensile strength, tensile elongation and tensile toughness by ca 20%, 55% and 90%, respectively. The thermal stability and water contact angle remained unaffected with the addition of TBCP.

Designing new eco-friendly fibers enable the creation of an alternative resource for many applications, specifically within the field of polymeric composites. This article details the fabrication of hybrid epoxy composites comprising natural fiber, Phoenix pusilla plant dry leaves which belong to the family of date palm and nanofillers made from the fish bones, which has been explored for the first time. ASTM standards provided the guidelines for the preparation of samples and mechanical measurements. The mechanical properties of the pure carbon fiber composites were compared with that of the hybrid composites containing carbon fiber, natural fiber and nanofiller. The results validate the potential of hybrid composites containing novel fibers. Adding the bio-nanofillers in hybrid polymer composites permits the enhancement of the tensile strength, flexural strength, and hardness by 22.5, 200, 100 and 15.2%, respectively.

Graphene based room temperature flexible nanocomposites were prepared using epoxy thermosets for the first time. Flexible behavior was induced into the epoxy thermosets by introducing charge transfer complexes between functional groups within cross linked epoxy and room temperature ionic liquid ions. The graphene nanoplatelets were found to be highly dispersed in the epoxy matrix due to ionic liquid cation–π interactions. It was observed that incorporation of small amounts of graphene into the epoxy matrix significantly enhanced the mechanical properties of the epoxy. In particular, a 0.6 wt% addition increased the tensile strength and Young’s modulus by 125% and 21% respectively. The electrical resistance of nanocomposites was found to be increased with graphene loading indicating the level of self-organization between the ILs and the graphene sheets in the matrix of the composite. The graphene nanocomposites were flexible and behave like ductile thermoplastics at room temperature. This study demonstrates the use of ionic liquid as a compatible agent to induce flexibility in inherently brittle thermoset materials and improve the dispersion of graphene to create high performance nanocomposite materials.

Nanocomposites comprising carbon nanofibers (CNF) were prepared and evaluated in terms of morphology, mechanical performance, thermal stability and crystallization properties. It was found that addition of CNF reinforced polypropylene (PP) matrix by marginally increasing the strength and modulus, but at the expense of toughness and ductility. To improve the toughness of the composites, polystyrene-block-poly(ethylene-ran-butylene)-block-polystyrene (SEBS) was used. Presence of SEBS remarkably improved the toughness and ductility of the composites. The optimum level of reinforcement was observed at 0.1 wt% of CNF in the composites. Phase morphology studies revealed that at this concentration, CNF were well dispersed in polymer phases and beyond it, agglomeration occurred. PP/SEBS/CNF (0.1 wt%) nanocomposites exhibited good strength, excellent toughness and decent modulus, which make them suitable for cost effective, light-weight, tough and stiff material for engineering applications. It was observed that thermal stability of composites is only marginally improved whereas crystallinity of PP drastically reduced by the addition of CNF. POLYM. COMPOS., 2015. © 2015 Society of Plastics Engineers

The present study focuses on the preparation of a novel hybrid epoxy nanocomposite with glycidyl polyhedral oligomeric silsesquioxane (POSS) as nanofiller, carboxyl terminated poly(acrylonitrile-co-butadiene) (CTBN) as modifying agent and diglycidyl ether of bisphenol A (DGEBA) as matrix polymer. The reaction between DGEBA, CTBN, and glycidyl POSS was carefully monitored and interpreted by using Fourier transform infrared (FTIR) and differential scanning calorimetry (DSC). An exclusive mechanism of the reaction between the modifier, nanofiller, and the matrix is proposed herein, which attempts to explains the chemistry behind the formation of an intricate network between POSS, CTBN, and DGEBA. The mechanical properties, such as tensile strength, and fracture toughness, were also carefully examined. The fracture toughness increases for epoxy/CTBN, epoxy/POSS, and epoxy/CTBN/POSS hybrid systems with respect to neat epoxy, but for hybrid composites toughening capability of soft rubber particles is lost by the presence of POSS. Field emission scanning electron micrographs (FESEM) of fractured surfaces were examined to understand the toughening mechanism. The viscoelastic properties of epoxy/CTBN, epoxy/POSS, and epoxy/CTBN/POSS hybrid systems were analyzed using dynamic mechanical thermal analysis (DMTA). The storage modulus shows a complex behavior for the epoxy/POSS composites due to the existence of lower and higher crosslink density sites. However, the storage modulus of the epoxy phase decreases with the addition of soft CTBN phase. The Tg corresponding to epoxy-rich phase was evident from the dynamic mechanical spectrum. For hybrid systems, the Tg is intermediate between the epoxy/rubber and epoxy/POSS systems. Finally, TGA (thermo gravimetric analysis) studies were employed to evaluate the thermal stability of prepared blends and composites. POLYM. COMPOS., 2015. © 2015 Society of Plastics Engineers

International audience; We investigated the phase separation, cure kinetics and thermomechanical properties of diglycidyl ether of bisphenol-A/4,4-diaminodiphenylsulfone/poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) (PEO-PPO-PEO) triblock copolymer (TBCP) blends. Fourier transform infrared spectroscopy, differential scanning calorimetry, and atomic force microscopy revealed that the blends exhibited heterogeneous phase morphology in which the TBCP formed dispersed domains in epoxy matrix, due to reaction induced phase separation. A fraction of phase-separated PEO phase underwent partial crystallization whereas another fraction formed interphases between the dispersed domains and epoxy matrix. Moreover, the dispersed PEO chains improved the compatibility and interfacial adhesion between the matrix and domains and, consequently, significantly improved the mechanical properties of epoxy resin. Furthermore, the thermal degradation studies and contact angle measurements disclosed that the dispersed domains were well protected by the epoxy matrix. (c) 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44406.

The polylactic acid is modified with porous silica-containing varying amount of capsicum oleoresin. The effect of accelerated weathering on the polymer degradation, thermomechanical, antibacterial, and rheological properties was studied. The accelerated weathering test was performed for 260 and 520h. The prepared composites show antimicrobial activity against gram-positive and gram-negative bacteria. The tensile strength, modulus, and percentage crystallinity of the composites increased by 17, 7, and 33% respectively with the addition of 1.54 wt% of capsicum oleoresin impregnated porous silica. On the other hand, the incorporation of capsicum oleoresin impregnated porous silica reduced shear modulus and shear viscosity of the composite films. The accelerated weathering, reduced tensile properties, thermal stability, and rheological properties; however, the percentage crystallinity was increased due to the chain scission of the polymer chains. The combination of ultraviolet irradiation, temperature, and humidity caused by the weathering test marginally reduced the antibacterial properties of the polymer films.

Bionanocomposites are promising green sustainable materials useful for diagnostic and biomedical applications. In the present study, cellulose/copper nanoparticles (CuNP) bionanocomposites were prepared using a bioflocculant as a reductant of the precursor copper ions for the in situ generation of CuNP in the cellulose matrix.. The novel bionanocomposite material was characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), antibacterial and corrosion tests. TEM, SEM, EDS, and XRD studies indicated the in situ generation of CuNP in the cellulose matrix. FTIR analysis proved no new bond formation between CuNP and cellulose films. Thermogravimetric analysis indicated single step degradation for neat cellulose whereas the bionanocomposites exhibit multi-step thermal degradation. The new bionanocomposite prepared with a copper precursor concentration of 250 mM was found to exhibit remarkable biocidal activity against E. coli with a zone of clearance of 12 mm and also good corrosion resistance.

Poly(methyl methacrylate)/poly(styrene-co-acrylonitrile) (PMMA/SAN) blends, with varying concentrations, were prepared by melt-mixing technique. The miscibility is ensured by fixing the acrylonitrile (AN) content of styrene acrylonitrile (SAN) as 25% by weight. The blends were transparent as well. The Fourier transform infrared spectroscopic (FTIR) studies did not reveal any specific interactions, supporting the well accepted 'copolymer repulsion effect' as the driving mechanism for miscibility. Addition of SAN increased the stability of PMMA towards ultraviolet (UV) radiations and thermal degradation. Incorporation of even 0.05% by weight of multi-walled carbon nanotubes (MWCNTs) significantly improved the UV absorbance and thermal stability. Moreover, the composites exhibited good strength and modulus. However, at higher concentrations of MWCNTs (0.5 and 1% by weight) the thermo-mechanical properties experienced deterioration, mainly due to the agglomeration of MWCNTs. It was observed that composites with 0.05% by weight of finely dispersed and well distributed MWCNTs provided excellent protection in most extreme climatic conditions. Thus, PMMA/SAN/MWCNTs composites can act as excellent light screens and may be useful, as cost-effective UV absorbers, in the outdoor applications.

Self-healing bio-based epoxy blends of poly(ethylene glycol)-poly(propylene glycol)-poly(ethylene glycol), (PEG-PPG-PEG) triblock copolymer (TBCP) was prepared and investigated, with the goal of developing smart self-healing coatings that can protect metal surface from corrosion. The epoxy blends consist of low molecular weight triblock copolymer (L61) blended in different weight percentage (5, 10, 20, 30, 40 and 50 wt%) were prepared. A room temperature curing agent was selected and the thermal mending of bioepoxy coatings are investigated. At an elevated temperature (ca.140 °C–150 °C), the TBCP phase undergoes mending and migrate to the crack site, forming a thin layer of protective coating on the substrate (carbon steel). The system was transparent up to 5 wt% TBCP content and are opaque above 10 wt% TBCP concentrations. The contact angle reduced considerably from 72.5° to 25.5° due to the hydrophilic nature of TBCP. The thermal stability was increased, while the mechanical properties were decreased by the addition of TBCP.

Sappan dye, a natural dye extracted from sappan wood is widely used in cosmetics, textile dyeing and as food additives. However, it was recognized that natural dyes cannot withstand high temperature. In this study, a protective coating of melamine-formaldehyde shell material was applied over the sappan dye to improve its thermal stability. The percentage of sappan dye used in the microencapsulation was 30, 40, 50, 60 and 70 wt%. The color, shape, size, and thermal stability of sappan dye microcapsules were investigated. It was found that increasing amount of sappan dye content in the microcapsules decreased the particle size. Thermal analysis reveals that the melamine-formaldehyde resin served as an efficient protective shell for sappan dye. Besides, 30 wt% sappan dye microcapsules with different weight percent (1, 3 and 5 wt%) of sappan dye was used as modifier for polypropylene (PP). All the prepared composites are red in color which supports the thermal stability of the microcapsules. The changes in crystallinity and melting behavior of PP by the addition of microcapsules were studied in detail by differential scanning calorimetry. Thermogravimetric studies showed that the thermal stability of PP composites increased by the addition of microcapsules.

This study demonstrates flame retardant materials designed using bi-phasic polymer blends of acrylonitrile butadiene styrene (ABS) and polyvinylidene fluoride (PVDF) containing halloysite nanotubes (HNTs) and Cloisite 30B nanoclay. The prepared blends with and without nanoparticles were extensively characterized. The nanoparticles were added in different weight concentrations to improve the flame retardancy. It was observed that prepared ABS/PVDF blends showed better flame retardancy than ABS based composites. The flame resistance was further improved by the addition of nanoparticles in the blends. The microscale combustion calorimetry (MCC) test showed better flame resistance in ABS/PVDF blends filled with 5 wt% HNTs than other composites. The total heat release of ABS/PVDF blend filled with 5 wt% HNTs decreased by 31% and also the heat of combustion decreased by 26% as compared to neat ABS. When compared with nanoparticles, the addition of PVDF reduced the peak heat release rate (PHRR) and increased the char residue more effectively. A synergistic improvement was observed from both PVDF and HNTs on the flame resistance properties.