Influence of emulsification on the properties of styrene-butadiene-styrene chemically modified bitumens

The effect of emulsification on the styrene-butadiene-styrene (SBS) chemically modified bitumens (CMBs) is studied by conventional tests, differential scanning calorimetry (DSC) and fourier transform infrared (FTIR) spectroscopy. Compared to CMBs, modified bitumen emulsion residues (MBERs) exhibit higher temperature susceptibility, inferior resistant to cracking and deformation, lower elastic recovery and storage stability whereas these properties are improved substantially relative to base bitumens. DSC results show that the thermostability of CMBs decreased slightly after emulsification which indicate the emulsification exerts very little effect on the thermal property of CMBs. The FTIR results do not indicate any chemical reaction exists on CMBs during the emulsification.

Preliminary investigations into using eugenol to recover erased characters on polymers

In this paper we present our preliminary studies on the efficacy of eugenol for the recovery of erased characters on polymers. We have found that eugenol rapidly recovers erased characters when applied to the surface of polymer substrates. By applying eugenol to the surface to be treated using a cotton bud or paintbrush, we were able to revisualize erased characters from a range of polymers, inclluding acrylonitrile butadiene styrene, acrylic, high-impact polystrene, and polystyrene. Eugenol is safe, nonhazardour, and easily sourced reagent for this purpose.

Carbon nanotube based elastomer composites-an approach towards multifunctional materials

The current study focuses on giving a basic understanding of tubular graphene sheets or carbon nanotubes (CNTs) and points towards their role in fabricating elastomer composites. Since the properties and the performance of CNT reinforced elastomer composites predominantly depend on the rate of dispersion of fillers in the matrix, the physical and chemical interaction of polymer chains with the nanotubes, crosslinking chemistry of rubbers and the orientation of the tubes within the matrix, here, a thorough study of these topics is carried out. For this, various techniques of composite manufacturing such as pulverization, heterocoagulation, freeze drying, etc. are discussed by emphasizing the dispersion and alignment of CNTs in elastomers. The importance of the functionalization technique as well as the confinement effect of nanotubes in elastomer media is derived. In a word, this article is aimed exclusively at addressing the prevailing problems related to the CNT dispersion in various rubber matrices, the solutions to produce advanced high-performance elastomeric composites and various fields of applications of such composites, especially electronics. Special attention has also been given to the non-linear viscoelasticity effects of elastomers such as the Payne effect, Mullin's effect and hysteresis in regulating the composite properties. Moreover, the current challenges and opportunities for efficiently translating the extraordinary electrical properties of CNTs to rubbery matrices are also dealt with.

Experimental investigation on bonding properties of reactive liquid rubber epoxy in CFRP retrofitted concretet members

The load bearing capacity of aging reinforced concrete structures, such as bridges, is increasingly extended with the use of Carbon Fibre Reinforced Polymer (CFRP). Premature failure, which is attributed to the rigid behaviour of the bonding agent (epoxy resin) and the high stresses at the interface region, can occur because of the debonding of CFRP sheets from host surfaces. To overcome the debonding issue, the epoxy resin is modified by different reactive liquid polymers to improve its toughness, flexibility, adhesion, and impact resistance. This study reports the usage of two reactive liquid polymers, namely, liquid Carboxyl-Terminated Butadiene-Acrylonitrile (CTBN) and liquid Amine-Terminated Butadiene-Acrylonitrile (ATBN), to improve the mechanical properties of the commercially available MBrace saturant resin when added to a ratio of 100:30 by weight. The neat and modified epoxies were analysed using the Dynamic Mechanical Thermal Analysis (DMTA) to determine and compare the storage modulus and glass transition temperatures of these materials. Moreover, the bonding strength of neat and modified epoxies was evaluated through single-lap shear tests on CFRP sheets bonded to concrete prisms. The results indicate that the modified resins exhibited improved ductility and toughness and became reasonably flexible compared with the neat epoxy resin. The improved properties will help delay the premature debonding failure in CFRP retrofitted concrete members.