Search results

This paper presents a method for the determination of the kinetic parameters for the oxidation‐reduction hardening reactions of unsaturated polyesters with styrene. The method was based on the measurement of the change in the specific internal electric resistance during the hardening. This paper discusses the accelerating effects of ferrocene and some of its derivatives (acetylferrocene, benzoylferrocene, 1,1′‐diethylferrocene) on the hardening of unsaturated polyesters.

This study aims to deal with both the development and mechanical investigations of unsaturated polyester matrix (UPR) composites containing recycled polyethylene terephthalate (PET) fibers as new fillers.

UPR/PET fibers composites have been developed as mats by incorporating 5, 8, 13 and 18 parts per hundred of rubber (phr) of 6-, 10- and 15-mm length PET fibers from the recycling of postconsumer bottles. The mechanical and physical properties of the composites were investigated as a function of fiber content and length. A significant increase in stress at break and in ultimate stress (sr) were observed for composites reinforced with 5 and 8 phr of 15-mm length PET fibers. The Izod impact strength of UPR/mat PET fiber composites as a function of fiber rate and length showed that the 5 and 8 phr composites for the 15-mm length PET fiber have the optimal mechanical properties 13.55 and 10.50 Kj/m², respectively. The morphological study showed that the strong adhesion resulting from the affinity of the PET fiber for the UPR matrix. The ductile fracture of materials reinforced with 5 and 8 phr is confirmed by the fiber deformation and fracture surface roughness.

This study concluded that the PET fiber enhances the properties of composites, a good correlation was observed between the results of the mechanical tests and the structural analysis revealing that for the lower concentrations, the PET fibers are well dispersed into the resin, but entanglements are evidenced when the fiber content increases.

It can be shown from scanning electron microscopy micrographs that the fabrication technique produced composites with good interfacial adhesion between PET fibers and UPR matrix.

Thixotropy can be regarded as the loss of viscosity in a paint or other material that is brought about by mechanical agitation, and where the viscosity continues to decrease provided that this disturbance is continued for a period of time. Conversely, when the mechanical force is removed, the material then increases in viscosity and this recovery toward the initial structure continues to take place over a period of time. Sometimes the time dependency of the viscosity is vanishingly small so that the material is then properly referred to as pseudoplastic. In most of the literature, however, it is not usually possible to differentiate between thixotropy and true pseudoplasticity and therefore both kinds of structure are included in this review as they each are destroyed by mechanical agitation and recover when this is discontinued.

Over the past two years the coating manufacturers have made their contribution to holding down inflation by only minimal price increases, even following last year's UK withdrawal from the ERM, which forced up the cost of raw material imports. Substantial price rises are now inevitable following the increased prices in the UK from leading suppliers for titanium dioxide by around 10 per cent.

The growing environmental awareness all through the world has motivated a standard change toward planning and designing better materials having good performance, which are very much suited to the environmental factors. The purpose of this study is to investigate the impact on mechanical, thermal and water absorption properties of sawdust-based composites reinforced by epoxy, and the amount of sawdust in each form.

Manufacturing of the sawdust reinforced epoxy composites is the main area of the research for promoting the green composite by having good mechanical properties, biodegradability or many applications. Throughout this research work, the authors emphasize the importance of explaining the methodology for the evaluation of the mechanical and water absorption properties of the sawdust reinforced epoxy composites used by researchers.

In this paper, a comprehensive review of the mechanical properties of sawdust reinforced epoxy composite is presented. This study is reported about the use of different Wt.% of sawdust composites prepared by different processes and their mechanical, thermal and water absorption properties. It is studied that after optimum filler percentage, mechanical, thermal properties gradually decrease, but water absorption property increases with Wt.% of sawdust. The changes in the microstructure are studied by using scanning electron microscopy.

The novelty of this study lies in its use of a systematic approach that offers a perspective on choosing suitable processing parameters for the fabrication of composite materials for persons from both industry and academia. A study of sawdust reinforced epoxy composites guides new researchers in the fabrication and characterization of the materials.

The purpose of this paper is to develop a volatile organic component‐free water‐based binder with improved coating properties from urethane‐alkyd acrylate by emulsion polymerisation.

Alkyd resin based on interesterification of sardine fish and linseed oil (50:50 w/w) was synthesised and reacted with isophorone diisocyanate to form urethane alkyd. The resultant urethane alkyd and acrylic monomers in different ratios were polymerised by emulsion polymerisation to form air‐drying water‐based binders and studied for physicochemical and other coating properties.

Urethane alkyd, co‐polymerised with acrylates by emulsion polymerisation process, can be used to prepare water‐based air‐drying binders with excellent coating and application performance. The increase in acrylate component in the system resulted in improvement of performance properties.

In the present study, refined fish oil (FO) was obtained from sardine fish. Different FOs can be used to produce alkyd resin. Urethane alkyd and acrylic monomers in different ratios can be polymerised by emulsion polymerisation techniques.

The emulsion polymerisation is the most effective technique used to produce water‐based binders with excellent coating properties.

Water‐based binders can be widely used in exterior coatings and waterproofing of cement and roofs.

DuPont has announced a new TiO2 R‐104 titanium pigment specially designed to provide outstanding optical and Theological performance at higher loadings in masterbatch formulations. With the new product, polyolefin masterbatch producers can, it is stated, achieve much higher ratios of R‐104 to resin; film producers can operate with greater efficiency at higher temperatures because of the low volatility of the product.

Fire retardant materials made of unsaturated polyester resin containing different halides and antimony trioxide were studied. In the present work the addition of a substance rich in halogen such as polyvinylchloride (PVC) and antimony trioxide Sb₂O₃ to the composite made of unsaturated polyester and fiberglass as a reinforced material has been studied. The addition of fire retardant material (PVC) and (Sb₂O₃) enhanced the fire retardancy of the product with remarkable low effect on the mechanical properties of the products. The electrical properties of the products are studied.

The purpose of this study is to develop jute-glass hybrid fibre reinforced polyester-based bio-composites using an indigenously developed pultrusion set-up and to present a detailed discussion on their mechanical characterization.

The work was carried out to observe the hybridization effect of natural and synthetic fibres in combination with hybrid fillers loading mainly on strength and other properties. The used hybrid fillers were a combination of 9 Wt.% of carbon black%, 6 Wt.% of eggshell ash powder and 6 Wt.% of coconut coir ash powder. A lab-based developed pultrusion set-up was used to develop these hybrid GJFRP composites of 1,500 mm length. The developed composites were tested for tensile strength, compressive strength and impact strength.

The maximum tensile, compressive and impact strength obtained are 88.37 MPa, 56.13 MPa and 731.91 J/m from 9 Wt.%, 9 Wt.% and 0 Wt.% of hybrid fillers loading, respectively. Breaking energy was found maximum as 7.31 J in hybrid glass-jute hybrid fibre reinforced plastic composites with no filler loading and it was observed that filler loading was decreasing the impact strength of developed hybrid composites. Shrinkage and its variations in the diameter of the finally developed cylindrical shape composites were observed after cooling and solidification. Scanning electron microscopy was used to observe the internal cracks, bonding of fibres and resin, voids, etc.

Development of hybrid filler based novel eco-friendly bio-composites and its experimental investigation on the impact strength, tensile strength and compressive strength has not been attempted yet.

To study the effect of addition of free diols and triols in the coating formulation on coating properties.

Polyester resins were synthesised from maleic anhydride, dimerised fatty acid, neopentyl glycol and tris (2‐hydroxyethyl) isocyanurate (THEIC). Then, ethylene glycol, propylene glycol, glycerol, trimethylol propane and THEIC were added as reactive components to the coating formulation. These coatings were then analysed for various coating properties and compared with those obtained with the base resins.

The coatings obtained with the addition of these reactive components were found to have improved properties compared with those of the base resins except in cases where the reactive component itself contributed to a reduction in performance, e.g. reduced alkali resistance with the addition of THEIC.

The addition of the free diols and triols required a corresponding increase in the amount of the curing agent to be added.

This process would allow for the tailoring of coatings to suit requirements to a certain extent without modifying the base resin. The addition of low molecular weight components in the coating formulation, which is then incorporated in coatings, could reduce the solvent requirement.

Although polyesters are an established polymeric system in coatings, the use of reactive diluents has not been investigated with the exception of unsaturated polyesters, whose curing chemistry is fundamentally different from that of polyesters focused on in this paper.