ADVANCES IN TECHNIQUES AND APPLICATIONS OF RUBBER SURFACE GRAFTING MODIFICATION

ABSTRACT To meet the requirement in the application of medical devices, composites, biomaterials, corrosion resistance, and selective adsorptions, rubber surface modification is usually indispensable. Grafting treatment is one of most significate treatment methods. In this paper, we focus on rubber surface grafting modification, including grafting techniques and applications. Different grafting methods—including monomer grafting polymerization and coupling reaction—are covered and compared briefly. The related applications of surface grafting modification techniques, such as improving compatibility of waste rubber as fillers, hydrophobicity and lipophilicity of sponge rubber for oil–water separation, biocompatibility of rubber in the medical field, and forming surface patterns, are demonstrated in detail. The new research directions of surface grafting techniques as well as main challenges in application are also discussed.

Preparation of High-Performance Composite Hydrogel Reinforced by Hydrophilic Modified Waste Rubber Powder

In order to reduce the environmental pollution caused by waste rubber and to realize the recycling of resources, we proposed a facile method for the hydrophilic modification of waste rubber powder (HRP) and used it to reinforce a composite hydrogel. In the presence of toluene, dibenzoyl peroxide (BPO) diffused into the waste rubber powder. After the solvent was removed, BPO was adsorbed in the rubber powder, which was used to initiate the grafting polymerization of the acrylamide monomer on the rubber–water interface. As a result, the polyacrylamide (PAM) molecular chains were grafted onto the surface of the rubber powder to realize hydrophilic modification. The success of the grafting modification was confirmed by FTIR, contact angle testing, and thermogravimetric analysis. The hydrophilic modified waste rubber powder was used to reinforce the PAM hydrogel. Mechanical tests showed that the tensile strength and elongation at the break of the composite hydrogel reached 0.46 MPa and 1809%, respectively, which was much higher than those of pure PAM hydrogel. Such a phenomenon indicates that the waste rubber particles had a strengthening effect.

Research Progress on Chemical Modification and Application of Cellulose: A Review

Cellulose is a rich natural polymer material, which has the characteristics of biodegradability, environmental friendliness and good biocompatibility. However, compared with conventional materials, there are some shortcomings in performance, such as intolerance corrosion, limited strength and so on. The chemical modification of cellulose not only retains its own excellent characteristics, but also introduces functional groups to endow it with specific properties. The chemical modification and utilization of cellulose has been the focus of research. In this paper, the latest advances in chemical modification of cellulose, such as esterification, etherification and grafting modification, are introduced. The research and application results of cellulose derivatives in food, wastewater treatment, medicine and papermaking in recent years are reviewed.

Rubber-to-steel adhesives based on natural rubber grafted with poly(acetoacetoxyethyl methacrylate)

The present study aimed to develop adhesives for bonding natural rubber (NR) to steel based on modified NR bearing grafted poly(acetoacetoxyethyl methacrylate), NR-g-PAAEM. Graft copolymers of NR-g-PAAEMs were prepared by emulsion polymerization at 50 °C. A significant increase in the polar component of NR from 1.62 to 6.84 mN/m was observed after grafting modification, indicating an increase in its hydrophilicity. After that, both one-coat and two-coat adhesives (or adhesive/cover-coat system) were then prepared, using polyisocyanate (poly‐HDI) as a bonding agent. The NR/steel joints were made by vulcanization bonding, using the NR-g-PAAEM adhesive in the presence or absence of cover-coat layer. The results reveal that the NR/steel joint bonded using the two-coat system exhibited higher peel strength than that bonded using the one-coat system. For the two-coat system, the peel strength of 874 N/m was attained when the NR-g-PAAEM adhesive was used in combination with the NR cover-coat. The replacement of the NR cover-coat by the NR-g-PAAEM20 cover-coat led to 49% increase in peel strength of the NR/steel joint. Moreover, the X-ray photoelectron spectroscopy analysis also indicated the formation of urethane-like bonding in this adhesive system, as a result of the reaction between the poly‐HDI and metal oxides on the steel surface.