Particulate polymer composites of Isophthalate based unsaturated polyester resin filled with different concentrations of lead monoxide were prepared. These composites were investigated for physical, thermal, mechanical, and gamma radiation shielding characteristics. The results of density evaluation, microscopic studies, and the radiation shielding properties for gamma rays of energy 0.662 MeV from Cs-137 point source have been presented in this article. The results show that, the density of the composites was observed to increase with filler loading. The morphological analysis of the composites made using the scanning electron microscope showed that, the lead monoxide particles were observed to disperse uniformly in the polymer matrix with an average inter particle distance of about 10 lm and an average size of about 5.36 lm. The linear attenuation coefficient of the composites was found to increase with increased filler content in the composites. The highest value of 0.206 cm À1was found for 50 wt % of lead monoxide. These composites were observed to exhibit excellent % of heaviness and Half value layer in comparison with other conventional materials.

In recent years, interest in agro polymers has created great interest among researchers and industry alike, as these materials are found to be biodegradable and eco‐friendly. Since the fossil fuel based polymers have created greater environmental concern, these bio‐based polymers are addressing the concerns in some of impactful areas such as food packaging and contribute significantly to the sustainable development with minimum ecological problems. Among agro polymers, starch based polymers have made major stride to marketable products in food packaging field. It is estimated that by the year 2020, the biocomposite materials demand will touch 20% of total plastic utilization. This review enlightens various processing techniques used to produce starch based polymers and composites with their properties to address the poor properties of starch. Low toxic and good compatibility natural plasticizers are of great interest in the processing of thermoplastic starch (TPS). Further emphasis is also given on essential packaging film properties such as barrier, biodegradation, mechanical, and thermal properties for TPS based materials. The overview of literature indicates that, Final properties of the thermoplastic starch can be improved by using different fillers, as well as by changing the source of the starch. Since the quest to produce better, cheaper, and eco‐friendly materials never stops, a multidisciplinary approach is required to achieve further improvement in the existing materials and to produce new class of materials that are eco‐friendly which can extend smarter and efficient services to customers. POLYM. COMPOS., 39:2499–2522, 2018. © 2016 Society of Plastics Engineers

Particulate polymer composites of Isophthalate based unsaturated polyester resin filled with different concentrations of lead monoxide were prepared and investigated for physical, thermal, mechanical, and gamma radiation shielding characteristics. The results of thermomechanical studies have been discussed in this article. The composites were investigated to understand the effect of filler on glass transition temperature (T g ) and thermal expansion coefficients (a) at various temperatures under cyclic heating and cooling conditions. The results show that T g values of composites appear to decrease slightly with increasing filler content. The composites were observed to exhibit three phases of thermal expansion during first heating and cooling cycles where as they exhibit only two phases during second heating cycle. An anomalous expansion of the composites was observed in the temperature range from 60 C to 110 C only during first heating and it disappears in subsequent heating cycles. Further, all the composites were observed to exhibit a dimensional contraction only during first heating and cooling cycles. The cyclic heating and cooling technique using thermo-mechanical analyzer was observed to be very efficient in determining actual values of T g and also in determining the post curing temperatures of the polymer and its composites.

The influence of polypropylene fibers on the thermal degradation of epoxy composites was investigated with thermogravimetric analysis. Three composites with 5, 10, or 15 wt % polypropylene fibers were prepared with epoxy as a matrix material. The polypropylene fibers, used as reinforcing materials, retarded the thermal decomposition, and increasing the weight percentage of the fiber material increased the thermal stability to a certain extent. Of the three composites, the 10 wt % polypropylene fiber/epoxy resin composite showed very good thermal stability, which was indicated by the increase in the resin decomposition temperature from 2808C for the 5 wt % polypropylene fiber/ epoxy resin composite to 3758C for the 10 wt % polypropylene fiber/epoxy resin composite. The Horowitz-Metzger method was used to calculate the activation energies, and the results were tabulated. A morphological analysis was carried out with scanning electron microscopy to evaluate the dispersion of the fibers in the epoxy matrix.

Polyols from chaulmoogra seed oil and grape seed oil were prepared by epoxidation and ring opening of oxirane ring using lactic acid in nitrogen atmosphere with a control over their functionality. Nanocellulose was derived from Desmostachya Bipinnata grass leaves and further surface functionalized. Modified nanocellulose was used as filler to prepare porous flexible bio-based polyurethane nanocomposites via in-situ polymerization. Adsorption of malachite green (MG) dye from wastewater using the prepared polyurethane composites was carried out. The effect of varying factors such as weight percentage of filers (modified nanocellulose), dosage of the adsorbent, pH, temperature and time on the MG adsorption have been studied experimentally. Material characterization for prepared materials was carried out using FTIR, NMR, TGA, DSC, and SEM along with other physical and chemical methods. FTIR results indicated the presence of peaks at 1704 cm−1 for –C=O stretching vibrations from urethane groups, 1531 cm−1 for –NH bending, 1232 cm−1 for –C–N stretching and 1105 cm−1 for –C–O stretching in the urethane group (–NHCOO–) thus, indicating the formation of urethane linkage in the polyurethane. Polyols with functionality around 2.8 were obtained from the oils, which has contributed to forming flexible polyurethanes. Morphological studies indicate the nano fibrillation of cellulose and closed-cell porosity in polyurethane and its composites. The flexible porous PU and its nanocellulose composites displayed improved thermal stability from 256.3°C to 270.5°C. Taguchi’s L27 orthogonal array have been applied for experimental design and optimization and the results were analyzed using ANOVA for raw and S/N ratio. It was found that pH is the most influential factor for adsorption lead by quantity of nanocellulose, time, dosage of the adsorbent and temperature.