PMMA blended and DPNR‐g‐PMMA coated DPNR and NR‐LA for dipping applications

Abstract

Deproteinized natural rubber (DPNR) latex, prepared by digesting the protein within low-ammonia preserved concentrated (NR-LA) latex with alcalase enzyme at 40°C for 24 h, has the nitrogen content of 0.039 wt %. Poly(methyl methacrylate) (PMMA) and graft copolymers (DPNR-g-PMMA) latices were synthesized by emulsion polymerization technique for blending or coating on DPNR or NR-LA. Their general properties of natural and synthesized latices including compounded latex were verified. The friction coefficient of a homogenous film obtained from PMMA blended DPNR or NR-LA latex and a DPNR-g-PMMA coated DPNR and NR-LA film was found to be lower than those of films prepared by using DPNR or NR-LA latex. Furthermore, the DPNR-g-PMMA coated films had lower friction coefficient than those of PMMA blended films. The physical properties in terms of 300% modulus, tensile strength, and elongation at break of those rubbers were tested and confined to the ASTM 3377-78a and ASTM 3378-99 standards for dipping products of surgical gloves and examination gloves, respectively.

Effects of methyl methacrylate grafting and in situ silica particle formation on the morphology and mechanical properties of natural rubber composite films

“…Thus, an increase in weight ratios of the PMMA grafted NR latex would tend to drastically reduce its elongation at break. [21,15] In general, most of the grafted NR latex is poor in film-forming properties as their mechanical properties do not meet the qualities set in ASTM-D3577 and ASTM-D3578 specifications for rubber surgical gloves and examination gloves but satisfactorily met the ASTM-D4679 specification for general purpose, household, or beautician rubber gloves. The mechanical properties were also affected by the addition of 5, 10, and 15 phr of TEOS, which was converted to silica in the rubber films.…”

“…[14] Graft copolymerization of MMA on the NR simultaneously improved the physical properties and reduced the tackiness of rubber films. [15][16] In the current work, an attempt was made to prepare graft copolymers of NRL and MMA using CHPO/TEPA as a redox initiator system. The grafted NRL was then subjected to silica reinforcement by in situ generation of silica during the latex curing process.…”

Influences of the grafting percentage of natural rubber‐graft‐poly(2‐hydroxyethyl acrylate) on properties of its vulcanizates

“…It provides excellent mechanical and dynamic properties such as high resilience, mechanical strength and fatigue resistance and low heat build‐up. Its molecular structure contains cis ‐1,4‐polyisoprene with an electron‐donating methyl group attached to the carbon–carbon double bond in its main chain, which can facilitate chemical modifications …”

“…Its molecular structure contains cis-1,4-polyisoprene with an electron-donating methyl group attached to the carbon-carbon double bond in its main chain, which can facilitate chemical modifications. 1 Graft copolymerization is an attractive technique to modify NR in order to provide new NR products, upgrade its physical properties and extend its uses. 2 Graft copolymerization allows desirable properties of different polymers to be combined in grafting products that inherit properties from both polymers.…”

Prediction of styrene conversion of polystyrene/natural rubber graft copolymerization using reaction conditions: Central composite design versus artificial neural networks

“…We attempted to explore the relationship between the styrene conversion and the graft copolymerization conditions, that is, reaction temperature and time, weight percent of deproteinized NR (DPNR) in the rubber mixture, and amount of CTA, as they have reportedly affected the conversion of vinyl monomer, for example, styrene and methyl methacrylate 8, 27, 28. DPNR that is NR with low nitrogen content was chosen to be one of factors herein because many research studies addressed its contribution to higher monomer conversion as proteins, which are adsorbed on rubber particles, can compete with monomer for radicals 28–31. Thus, instead of initiating polymerization of monomer, some radicals react with proteins.…”