In this research work, solution dispersion technique was employed for the preparation of segmented poly (azo-urethane)/multi-walled carbon nanotube (SPAU/MWCNT) nanocomposites whereas the polyurethane was obtained using single-step procedure. The carboxylated nanotube-based non-compatiblized SPAU/MWCNT and acid chloride functionalized MWCNT-based compatiblized systems were prepared. Afterwards, the hydroxyl end-terminated polyurethane was grafted to acid chloride functional MWCNT through esterification reaction. The grafting to the carboxylated nanotube was achieved via physical interaction. The FTIR spectra confirmed the covalent bonding between the matrix and side-walls of nanotube. Various nanotube loading levels and surface-modified groups were considered to regulate mechanical, thermal and electrical performance of SPAU/MWCNT. The experimental results showed that a moderate loading-level of 5 wt. % MWCNT produced the maximum tensile strength (63.1 MPa) in compatiblized nanocomposites, while the tensile strength of non-compatiblized SPAU/MWCNT was lower (47.25 MPa). Comparative studies based on scanning and transmission electron microscopy of the chemically bonded samples also revealed the covalent coating character and unique nano-fibriller morphology. The dynamic mechanical analysis of nanocomposites showed segmental rigidity due to covalent linking and sample had Tg of 142–152 °C. Addition of acid chloride functionalized MWCNT also contributed to an improvement in the electrical conductivity (2.01-4.31 S cm−1) relative to SPAU/carboxylated MWCNT 1.27-2.86 S cm−1.

High Density Polyethylene (HDPE) reinforced multiwalled carbon nano-tubes (MWCNTs) composites with MWCNTs loading between 0.0011 and 0.0044 volume fractions are fabricated by melt mixing. The prepared nano-composites are investigated by thermo-gravimetric analyzer (TGA) under nitrogen atmosphere at various heating rates. TGA thermograms indicate only a marginal enhanced thermal stability and no significant mass loss occurs up to ~400 °C. Thermal degradation kinetics of HDPE/MWCNTs nano-composites has been examined in light of five different analytical methods, viz., Coats-Redfern (CR) integral model fitting approach, ‘iterative’ based CR(modified) approach, integral form of the rate equation (i.e. FWO and KAS), the differential iso-conversional based method of Friedman. The CR integral model fitting based on 14 different kinetic models are analyzed for TGA data for multiple heating rates. Our analysis indicates that the degradation mechanism of the present nano-composites follows diffusion control (D2, D3 and D4) and first order reaction (F1) mechanisms. The apparent activation energy (E a ) as a function of conversion rate (α) estimated by CR (modified), FWO, KAS and FR methods are all in fair agreement with each other and confirms decrease in E a with increased loading of MWCNTs. The pre-exponential factor (A) calculated also decreases with MWCNTs concentration in HDPE. Activation energy (E a ) for different conversion rate (α) calculated by iso-conversional methods (CR(modified), FWO, KAS and FR) indicates contributions from at least two different degradation mechanisms, namely, diffusion controlled (D2, D3, D4) and first order reaction (F1), which are consistent with the findings of Coats-Redfern (CR) integral model.

The dry sliding wear characteristics of glass-epoxy (G-E) filled with soapstone filler was studied as per ASTM 99 standard by using a pin-on-disc test rig. The wear behavior was studied by varying the volume fraction of the filler ranges from 5 to 15 % in the composite. The composite was prepared by the hand lay-up technique. The specific wear rate was determined as a function of applied load, sliding velocity and sliding distance. The results revealed that, the specific wear rate increases as applied load and sliding distance increases in all the tested composites. However, composite filled with 5 % soapstone showed less specific wear rate.

This study discusses the influence of incorporation of natural fiber on the performance of recycled polypropylene composites. Composites consisting of polypropylene (PP) and sisal fiber were prepared through mixing and compression process, in various proportions. The surface modification of the fibers has been carried out, using various chemical treatments. Mechanical properties of the systems have been evaluated. A comparative study has been conducted between the theoretical as well as experimental results using various suitable models. The impact of treatment of the fibers on the thermal and flammability properties has also been investigated. The interfacial properties have been interpreted from scanning electron micrographs (SEM).

Novel thermoplast–thermoset merged polyimide system has been developed via Diels-Alder intermolecular reaction of bisfuran A namely, 2,5-bis(furan-2-ylmethyl carbamoyl)terephthalic acid with a series of bismaleimides B1–5 containing aliphatic and alicyclic groups in the main chain viz., B1: 1,2–bismaleimido ethane, B2: 2–methyl–1,5–bismaleimido pentane, B3: 1,6–bismaleimido hexane, B4: 2,2,4–trimethyl 1,6–bismaleimido hexane, B5: isophorone bismaleimide. The intermediate Furan—maleimide Diels-Alder adducts C1–5 were aromatized and imidized (i.e. cyclized) through carboxylic and amide groups to afford thermoplast-thermoset merged polyimides D1–5. Synthesized polyimides were characterized by elemental analysis, spectral features, number average molecular weight (\( \overline{\mathrm{Mn}} \)) and thermal analyses. Bulk polymerization was also carried out. Proof of structure was based mainly on a comparison of infrared spectra of polyimides with those of the corresponding model compound 4 prepared from phthalic anhydride and furan–2yl–methanamine in the similar way. FTIR spectral features of polyimides D1–5 were quite identical with the model compound 4. The ‘in situ’ void–free glass fiber reinforced composites GFRC1–5 were prepared and characterized by mechanical, electrical and chemical properties. The ‘in situ’ produced PIs show good adhesion to glass fibers. All the composites showed good mechanical and electrical properties and good resistance to organic solvents and mineral acids.

The Taguchi method is a powerful approach for solving quality problems in various aspects of the engineering field. Due to the increase of plastic parts consumption in each day, continuing customer satisfaction and economic viability in a competitive plastic industry environment are gaining tremendous attention. Thus, Taguchi method offers a simple yet systematic approach to optimize design for performance, enhancing the product quality and reduce the cost as well. A lot of studies have been conducted on the efficiency of this method. However a total comprehensive review of the implementation of the Taguchi method particularly in the plastic industry is limited. This paper presents an extensive review of past literature on the application of the Taguchi method in plastic industries focusing on product quality enhancing and obtaining the desired properties for new materials. From the review, it can be concluded that the Taguchi method has made extensive contribution to the plastic industry by bringing focused and awareness to robustness to improving quality.

In this research, various weight percent of EC plasticizer are incorporated into salted PEO based polymer electrolyte system. Thin film electrolytes are prepared via solution casting technique and characterized by FTIR, XRD and DSC analysis in order to study their complex behaviour. The amorphicity of the electrolytes are measured by DC Impedance. The results reveal that the conductivity increases with increasing temperature when the EC plasticizer concentration increases up to 15 wt%. The temperature conductivity studies for 15 wt%. of EC plasticizer decrease due to displacement of the host polymer by plasticizer molecules within the salt complexes. Thus, it will decrease in ionic mobility. XRD studies reveal that the phase changes from crystalline to amorphous when EC plasticizer concentration increases. DSC studies indicate a decrease in Tm with increasing EC plasticizer concentration. Finally, the complexation process is examined using FTIR.

The modification of epoxy resin with polysulfide polymer has been carried out by keeping the ratio of polysulfide polymer and epoxy resin as constant in order to avoid phase separation. The nanocomposites have been prepared by an ex-situ technique. The effect of nanosilica loading on mechanical property, thermo—mechanical properties, morphology, and dielectric properties has been studied. It is found that the tensile properties decrease with the increase in nanosilica loading for all the nanocomposites system except for 3 wt% nanosilica loading. This has been attributed to the better dispersion of nanosilica particles in modified epoxy matrix at 3 wt% loading compared to other systems which has been observed from transmission electron microscopy (TEM) images. Dynamic mechanical analysis (DMA) study shows that the storage modulus value and tanδ peak height is decreasing with the increase in nanosilica loading in the modified epoxy matrix. There is the increase in thermal stability with the incorporation of nanosilica in base polymer system. Dielectric study reveals that there is only one relaxation peak, and the dielectric constant value decreases with the increase in frequency as well as nanosilica loading. Fourier transfer infra-red (FTIR) study has also been carried out for the composite systems.

Copolymer of styrene and maleic anhydride (MAn) were copolymerized in N, N-dimethylformamide (DMF) as a solvent and benzoylperoxide as initiator at temperature 80°C . The monomer feed ratio of styrene (Sty) and maleic anhydride (MAn) was varied in the range of 1:1 to 3:1. The acid values were about 480, 357 and 295 where as the softening temperature were 155, 140 and 120 respectively. The synthesized copolymer were hydrolyzed by various alkali viz. NaOH, KOH and NH4OH. The above synthesized copolymer and alkali modified copolymers have been characterized by 1H-NMR, DSC, TGA, SEM Optical microscopy and percentage solid settling etc. The results showed a broad overlapping peak between 1.1 and 2.3 δ ppm and peaks between 7.0 and 7.4 ppm are due to methylene/methine and aromatic ring hydrogens of styrene respectively where as Methine protons of maleic anhydride appear between 3.1 and 3.6 ppm. The Tg of copolymer were found to be greater than that of polystyrene indicating formation of a copolymer. The thermal stability of the copolymers decreased with the increase in maleic anhydride content in the copolymer. The spherical shapes of beads can be ascertained from the microphotograph for molar feed of Sty/MAn as 1:1 and these becomes irregular for 2:1 and 3:1. Where as a fine network with smaller structure as well as the well dispersed grain taken by Scanning Electron Microscopy and Optical Microscopy confirms better dispersion of carbon black when these alkali modified SMA copolymers have been added. It was also found a remarkable decrease in percentage solids when alkali modified SMA were added in the system as compared to when no resin were added. This shows the addition of SMA not only improves dispersion but also improves the stability of the system. Application of these alkali modified SMA copolymers as a dispersing agent to disperse a non- polar particles like carbon black in water were studied with the help of Daniel Flow Method and found that the sodium salts of SMA copolymers having molar feed ratio of styrene to maleic anhydride as 1:1 showed best dispersion for Carbon Black particles.