Physicochemical Study of CPOL-701–Glass/Jute Composites

Glass and jute composites (CPOL-701-G and CPOL-701-J) have been fabricated by hand lay-up technique at 50°C under 27.6 MPa pressure for 3–4 h using MEKP and cobalt naphthenate. Both composites possess excellent tensile, flexural and dielectric strengths, volume resistivity and dielectric constant as well as hydrolytic stability against water, 10% aq. HCl and 10% aq. NaCl at 35°C. Cured CPOL-701 appears to be having good thermal stability (206°C) and high values of kinetic parameters. Excellent physicochemical properties of the composites signify their industrial importance.     

Composites of Poly(Keto-Sulfide)–Epoxy Resin Systems and Their Thermal and Mechanical Properties

A novel matrix resin system, poly(keto-sulfide)–epoxy resin, has been developed. The poly(keto-sulfide)s (PKS), based on various ketones, formaldehyde, and sodium hydrogen sulfide (NaSH), were prepared by the reported process. These (PKS) having terminal thiol (–SH) groups were used for curing commercial epoxy resin (i.e., diglycidyl ether of bisphenol A – DGEBA), to fabricate crosslinked epoxy-poly(keto-sulfide) resin glass fiber-reinforced composites (GRC). Various epoxy/hardener (PKS) mixing ratios were used, and the curing of epoxy-PKS has been monitored using differential scanning calorimetry (DSC) in dynamic mode. Based on DSC parameters the GRC of epoxy-PKS were prepared and characterized by thermal and mechanical methods. The variation in resin/hardener ratio led to variations in thermal and mechanical properties.     

Mechanical and Abrasive Wear Studies on Biobased Jatropha Oil Cake Incorporated Glass–Epoxy Composites

An investigation was made to evaluate the effect of the incorporation of jatropha oil cake (JOC) alone and in combination with silicon carbide (SiC) on the mechanical and tribological wear behaviour of glass fabric–epoxy (GE) composites. A vacuum-assisted resin transfer moulding (VARTM) technique was employed to obtain a series of GE composites containing different fillers viz., silicon carbide, jatropha oil cake and a mixture of SiC and JOC. The effect of different loads (22 and 32 N) and abrading distances from 135 to 540 m on the performance of the wear resistance of the composites were measured. The mechanical properties such as tensile behaviour and hardness of the composites were evaluated. A linear relationship was found between the wear volume loss and the abrading distances. The JOC filled GE composite exhibited a lower specific wear rate by 6 and 10% at 540 m abrading distance for a load of 22 and 32 N, respectively, as compared to that of unfilled GE composites. The worn surface features of unfilled and filled GE composites were examined using scanning electron microscopy (SEM).     

Evaluation of the Effect of Nanosilica on Thermal and Mechanical Properties of Metal–Metal and Metal–Glass Canola-Based Polyurethane/Nanosilica Adhesives

Nanocomposites with different concentration of nanofiller were prepared by adding nanosilica to the canola-based polyurethane matrix via in situ polymerization. The effect of nanosilica on the mechanical properties of adhesives was evaluated by tensile tests. Adhesive characteristics on metal–metal and metal–glass bondings were also evaluated by lap shear strength tests. Incorporation of nanosilica into the canola-based polyurethane enhanced both tensile and lap shear strength of synthesized adhesives. Also the effect of nanoparticles on glass transition temperature and thermal stability was investigated by differential scanning calorimetry and thermogravimetric analysis, respectively. The increase of nanosilica content in the polyurethane adhesives, thermal property of the nanocomposites improved.     

Reaction Synthesis and Mechanical Properties of TiB2–AlN–SiC Composites

TiB₂–AlN–SiC (TAS) ternary composites were prepared by reactive hot pressing at 2000°C for 60 min in an Ar atmosphere using TiH₂, Si, Al, B₄C, BN and C as raw powders. The phase composition was determined to be TiB₂, AlN and β-SiC by XRD. The distribution of elements Al and Si were not homogeneous, which shows that to obtain a homogeneous solid solution of AlN and SiC in the composites by the proposed reaction temperatures higher than 2000°C or time duration longer than 60 min are needed. The higher fracture toughness (6·35±0·74 MPa·m^1/2 and 6·49±0·73 MPa·m^1/2) was obtained in samples with equal molar contents of AlN and SiC (TAS-2 and TAS-5) in the TAS composites. The highest fracture strength (470±16 MPa) was obtained in TAS-3 sample, in which the volume ratio of TiB₂/(AlN+SiC) was the nearest to 1 and there was finer co-continuous microstructure. ©     

Polyaniline–Carbon Nanotube Composites: Preparation Methods,Properties, and Applications

Synthesis of polyaniline and hybrid carbon nanotube reinforced polyaniline nanocomposites by various methods has discussed in this review. Different routes used for functionalization of carbon nanotube have been reported. The electrical, mechanical, and thermal properties of polyaniline/carbon nanotube nanocomposites are also discussed. The dispersion of functionalized carbon nanotube, filler concentration, and their alignment in the interior of polyaniline matrix affect their morphology. Furthermore, article focussed upon the various morphologies of polyaniline and polyaniline/carbon nanotube nanocomposites obtained with different methods along with electrical conductivity. Possible applications of polyaniline/carbon nanotube nanocomposites in the areas of actuators, sensors, electromagnetic interference shielding have also discussed.     

Dielectric,Mechanical, and Thermal Properties of Low-Permittivity Polymer–Ceramic Composites for Microelectronic Applications

A new low-permittivity polymer–ceramic composite for packaging applications has been developed. The ceramic-reinforced polyethylene and polystyrene composites were prepared by melt mixing and hot molding techniques. Low-loss, low-permittivity Li₂MgSiO₄ (LMS) ceramics prepared by the solid-state ceramic route were used as the filler to improve the dielectric properties of the composites. The relative permittivity and dielectric loss were increased with the increase in the ceramic loading at radio and microwave frequencies. The mechanical properties and thermal conductivity of the Li₂MgSiO₄-reinforced polymer–ceramic composite were also investigated. The stability of the relative permittivity of polymer–ceramic composites with temperature and frequency was investigated. The experimentally observed relative permittivity, thermal expansion, and thermal conductivity were compared with theoretical models.     

In situ Reaction Synthesis and Mechanical Properties of TaC–TaSi2 Composites

TaC–TaSi₂ composites were fabricated at 1700°C by an in situ reaction/hot pressing method using Ta, Si, and graphite as initial materials. TaSi₂ content was 0–100 vol%. The microstructure and mechanical properties of the composites were investigated. It was found that the relative densities of composites were above 97.5% when the volume content of TaSi₂ was above 10%. The TaC/10 vol% TaSi₂ composite presented the highest flexural strength of 376 MPa. When the TaSi₂ content was 30–50 vol%, the composites showed the highest fracture toughness of about 4.3 MP·am^1/2. In addition, the composites could retain high Young's modulus up to at least 1525°C.     

Thermal and Mechanical Properties of Glass–Ceramics Based on Slate and Natural Raw Materials

Silicon - In recent years, utilization of raw materials was increased to produce natural low-cost glass–ceramic materials with distinct properties and appropriate for various applications....     

An In-depth Analysis of the Mechanical,Electrical, and Drug Release Properties of Gelatin–Starch Phase-Separated Hydrogels

Gelatin–starch-based phase-separated hydrogels were prepared in this study. Corn starch, soluble starch, and hydrated starch were used as the representative starches for the preparation of the hydrogels. Bright field microscopy suggested the formation of phase-separated hydrogels. An increase in the hydrophilic nature of the starch molecules resulted in decrease in the agglomeration of the starch particles within the gelatin matrices. Fourier transform infrared study confirmed the presence of starch particles within the hydrogels. X-ray diffraction studies suggested that the higher degree of crystallinity of corn starch and soluble starch was responsible for the comparative hydrophobic nature of these starch particles. Hydrated starch was found to be amorphous in nature and can be explained by the destruction of the intramolecular associative forces. Stress relaxation and creep recovery studies indicated predominant elastic nature of the hydrogels. Hydrated starch-containing hydrogels were firmer than corn starch and soluble starch because of the better miscibility of the hydrated starch particles within the gelatin matrices. The bulk resistance of the starch-containing hydrogels was higher. This was because of the capability of the starch particles to behave as dielectric medium. Incorporation of starch particles within the gelatin matrix was found to increase the polymer relaxation-mediated drug diffusion. Metronidazole-loaded hydrogels were found to have good antimicrobial activity.     

An in-Depth Analysis of the Swelling,Mechanical, Electrical,and Drug Release Properties of Agar–Gelatin Co-Hydrogels

Agar–gelatin-based co-hydrogels were prepared with different compositions of the agar and the gelatin fractions. The intermolecular hydrogen bonding was higher in the co-hydrogels as compared to the gelatin hydrogel. Swelling studies indicated diffusion-mediated swelling. The electrical stability of the co-hydrogels was higher as compared to the gelatin hydrogel. Though the firmness of the co-hydrogels was higher, Weichert model of viscoelasticity indicated that the inherent mechanical stability of the gelatin hydrogel was superior. The release of ciprofloxacin hydrochloride was predominately Fickian diffusion-mediated. In gist, the co-hydrogels can be tried as polymeric constructs for controlled drug delivery applications.     

Study on the Mechanical,Rheological, and Morphological Properties of Short Kevlar™ Fiber/s-PS Composites

This article deals with oxy-fluorinated short Kevlar^TM fiber reinforcement and its effect on the dynamic, mechanical, and rheological properties of the syndiotactic polystyrene composites. The composites were prepared using a twin-screw extruder at 20 rpm and the resulting composite was molded under injection molding. The study shows that the addition of oxy-fluorinated Kevlar^TM fiber into the syndiotactic polystyrene matrix significantly affects the dynamic mechanical properties of the composite by appreciably increasing storage modulus. Rheological properties reveal a significant enhancement of viscosity of the treated composite, due to the formation of a strong interface between fiber and matrix. Oxy-fluorinated fiber incorporation leads to improved tensile strength, elastic modulus, and impact strength of the resulting composite as a result of better fiber-matrix adhesion at the interface.     

Influence of TiO2-Modification on the Mechanical and Thermal Properties of Sugarcane Bagasse–EVA Composites

The effect of nano-particles of TiO₂ on the mechanical and thermal properties of sugarcane bagasse (SCB)–ethylene co-vinyl acetate (EVA) composite was investigated. Composite materials were prepared using a melt-mix intercalation method on a rheomex mixer coupled with a single screw extruder. differential scanning calorimeter (DSC), thermogravimetric (TG) analyser and an Instron, were used to probe the thermal and mechanical properties of the samples. Composites with TiO₂ were compared with those without TiO₂ but with the same content of sugarcane bagasse (SCB). After the addition of TiO₂, the tensile strength increased by 10%, from 11.26 MPa for neat EVA, which correlated with the enthalpy of fusion, however, the tensile strength decreased by 18% at higher SCB loading. Elongation at break decreased from 463 to 0% as the filler (SCB) was increased which was inversely proportional to the modulus. The composite showed an improved thermal stability with the addition of TiO₂.     

Development of Siloxane Based Tetraglycidyl Epoxy Nanocomposites for High Performance Applications—Study of the Thermo Mechanical,Electrical, XRD,EDS and Physical Properties

Silicon - A study was made in the present investigation on siloxane containing tetraglycidyl epoxy nanocomposites to find its suitability for use in high performance applications. The synthesis and...     

Mechanical and Bioactive Behavior of Hydroxyapatite–Wollastonite Sintered Composites

The effect of wollastonite amount on the mechanical and bioactive properties of several hydroxyapatite-wollastonite sintered composites was evaluated. The wollastonite reinforcement effect was assessed by measuring hardness and reduced elastic modulus on the materials, using nanoindentation methods. Bioactive properties were analyzed by soaking these materials in a simulated body fluid (SBF) for various periods of time. The analyses reveal an enhancement of hardness and reduced elastic modulus with the addition of wollastonite. In addition, the interaction of these materials with an SBF produces a bone-like apatite layer on their surfaces, which is thicker when the wollastonite is in a higher proportion.     

Processing and Characterisation of Epoxy–SiC Functionally Graded Polymer Matrix Composites

This paper proposed preparing and investigating the Epoxy–Silicon carbide composite for aerospace applications. In recent years aerospace industries concentrated in low weight, high strength and high thermal resistance materials. Polymer matrix composite can provide a better solution for the statement mentioned above. This study thermosetting study Epoxy and SiC materials have mixed in centrifugal casting with the ratio of 5%-SiC and resin. The microstructural evaluation is carried by Scanning Electron microscopic and investigating the tensile and hardness properties of the Epoxy– SiC Functionally Graded Polymer Matrix Composites. The wear and fracture analyse were investigated, and the results were discussed. the results show the SiC has provided the higher strength for composite, and its mixing percentage has control the weight of the polymer composite.

     

Degradation Studies of Thermoplastics Composites of Jute Fiber–Reinforced LDPE/Polycaprolactone Blends

This article reports the fabrication, properties, and degradation studies of jute fiber–reinforced thermoplastic polymers. One of the non-traditional outlets of jute fiber is in the area of fiber-reinforced composites. However, the major drawback associated with the application of jute fiber for this purpose is its high moisture regain. To impart hydrophobicity to the fibers and to concomitantly increase interfacial bond strength, which is a critical factor for obtaining better mechanical properties of composites, jute fibers were treated with benzoylchloride, Y-glycidoxytrimethoxysilane, and neo-alkoxy-tri(N-ethylenediamino)ethyltitanate. Such a treatment resulted in an increase in the diameter and denier of the treated fibers, and deterioration in the mechanical properties was observed. SEM studies revealed an increase in surface roughness after titanate and alkali treatment, which in turn increases interfacial bond strength. A series of low-density polyethylene (LDPE) blends with 5–20% (w/w) of poly(e-caprolactone) (PCL) and with/without treated and untreated jute fibers were prepared by using a single-screw extruder. LDPE modified by blending with PCL (80:20, wt/wt) was used as a thermoplastic matrix. Composites were fabricated by using 1-cm-long jute fibers; the weight fraction of unmodified fibers, silane-treated fibers, and titanate-treated fibers was varied from 0.05 to 0.13. An increase in weight fraction of fibers resulted in an increase in tensile strength and modulus and decrease in elongation at break. Thin sheets and dumbbells were used for enzymatic degradation tests. The degradation of the material was monitored by weight change and loss of mechanical properties. The enzymatic degradation in the presence of Pseudomonas cepacia lipase gave appreciable weight loss in PCL and blended materials.     

Time–Temperature-Transformation Cure Diagram of Multiwall Carbon Nanotube/Epoxy Composites

This work describes the effects of multiwall carbon nanotube on the isothermal time–temperature-transformation cure diagram to obtain a comprehensive cure map for a 2 wt% multiwall carbon nanotube/epoxy composite. The viscoelastic and thermal properties of the nanocomposites for a wide range of isothermal cure temperatures were obtained using a strain-controlled rheometer ARES TA and a differential scanning calorimetry. The thermal and rheological analyses were used to investigate the vitrification and the gelation of the nanocomposite, and to draw the time–temperature-transformation diagram. This diagram is completed by adding the iso-viscosity curves.     

Mechanical Properties and Microstructure of Nano-SiC–Al2O3 Composites Densified by Spark Plasma Sintering

Heterogeneous precipitation method has been used to produce 5 vol% SiC–Al₂O₃ powder, from aqueous suspension of nano-SiC, aqueous solution of aluminium chloride and ammonia. The resulting gel was calcined at 700°C. Nano-SiC–Al₂O₃ composites were densified using spark plasma sintering (SPS) process by heating to a sintering temperature at 1350, 1400, 1450, 1500 and 1550°C, at a heating rate of 600 °/min, with no holding time, and then fast cooling to 600°C within 2–3 min. High density composites could be achieved at lower sintering temperatures by SPS, as compared with that by hot-press sintering process. Bending strength of 5 vol% SiC–Al₂O₃ densified by SPS at 1450°C reached as high as 1000 MPa. Microstructure studies found that the nano-SiC particles were mainly located within the Al₂O₃ grains and the fracture mode of the nanocomposites was mainly transgranular fracture.     

Rheology and Mechanical Properties of PVC/Acrylonitrile–Chlorinated Polyethylene-Styrene/MAP-POSS Nanocomposites

The nanocomposite of the Poly(vinyl chloride)/acrylonitrile-chlorinated- polyethylene-styrene (ACS)/methylacryloylpropyl-contaning polyhedral oligomeric silsesquioxane (MAP-POSS) (PVC/ACS/MAP-POSS) was prepared. Plasticizing behavior, dynamic rheology behavior and mechanical properties of the nanocomposites were investigated. The results showed that the plastic time decreased with increasing MAP-POSS content. The dynamic storage modulus G ′, loss modulus G″ and complex viscosity η* of the nanocomposites all exhibit a monotonic change with increasing frequency, and all have maximum when MAP-POSS content is 4 wt%, at the same frequency. The MAP-POSS can be used as an efficient process aid and impact aid of PVC/ACS blend at appropriate content.