Liquid natural rubber

Materials. The epoxidation of liquid natural rubber (M = 8000) was carried out by mixing a chloroform solution of the polymer and an acetic acid solution of peracetic... 

Fig.2 Influence of the epoxy content on the photoinitiated cationic polymerization of epoxidized liquid natural rubber (ELNR). ( ) Photolysis of the photoinitiator ( A) [TAS] = 3 wt %.

As natural rubber is a product of nature, its properties are determined by the biochemical pathway by which the polymer is synthesized in the plant. In the case of natural rubber the polymerization process cannot be tailored like that of synthetic rubbers. The only option to modify natural rubber is after it has been harvested from the tree. The important modified forms of natural rubber include hydrogenated natural rubber, chlorinated natural rubber, hydro-halogenated natural rubber, cyclized natural rubber, depolymerised liquid natural rubber, resin modified natural rubber, poly(methyl methacrylate) grafted natural rubber, poly(styrene) grafted natural rubber, and epoxidized natural rubber [33,34]. Thermoplastic natural rubber prepared by blending natural rubber and PP is considered as a physically modified form of natural rubber. 

Liquid natural rubber, SBR, acrylonitrile elastomers, neoprene, and chlorosulfonated polyethylene are also used as sealant compositions. Filled depolymerized natural rubber and SBR latex are readily cured at room temperature by the incorporation of ultraaccelerators. 

NR/LLDPE 60/40 Liquid natural rubber (LNR6andLNR16) 3MeV e-beam 40 to 240 kGy 128... 

H. Polyester-kenaf composites Effects of alkali fiber treatment and toughening of matrix using liquid natural rubber. J. Compos. Mater. 45 (2011) 203-217. 

A pioneer group of researchers in UKM has extensively studied utilization of liquid natural rubber (LNR) as a compatibilizer on various NR/polyolefin blends. LNR was produced by photodegradation of NR in toluene and exposure to the ultraviolet for 6 h. The LNR has the same microstructure as NR but with a short polyisoprene chain (of diflerent molecular weight, M )- The Mw of LNR is around 50,000 whereas for NR is 900,000. The formation of new functional groups such as H, C-O and C=0 via oxidation of photochemical sensitization of NR. The presence of the new functional groups is shown in Figure 17.1. The LNR with some active terminals like -OH is... 

The ring opening reaction of naphthyl acetic acid with epoxidized liquid natural rubber (ELNR) (Fig. 33) under microwave irradiation was studied by Huy et al. [125]. The reactions were carried out in a chlorobenzene solution (1.2 ml) in a... 

Fig.33. Fixation of a-naphthyl acetic acid (NAA) onto epoxidized liquid natural rubber. Reprinted from (1996) J Mater Sci Pure Appl Chem A33 1957 [125] with permission...

It has been proved that the nature of solvent used for casting in the preparation of the blend influences the compatibility and related properties of PS-poly(vinyl methyl ether) (PVME) mixtures." Clear films of PS-PVME mixtures were obtained on casting from solvents like benzene, toluene, etc., while visually incompatible films result upon casting from trichloroethylene and chloroform. Blends of PVC and LNR/epoxidized liquid natural rubber (ELNR) were prepared using a common solvent, 2-butanone. ° Another research group prepared PVC/NR blends using THE as the solvent. ... 

Test formulations for pumpable sealants based on liquid natural rubber, liquid polybutadiene and liquid nitrile rubber are shown in Tables 8.10, 8.11, and 8.12, respectively. 

When liquid natural rubber is used as the sealant base, shear adhesion increased from 0 for the control to 4.55 MPa with 30 phr Saret 633. Heat ageing at 130 °C for 14 days increased the shear adhesion to 4.90 MPa. 

Segmented block copolymers, hydroxyl-terminated liquid natural rubber, a,(o-diisocyanato telechelic H block copolymer 279... 

Liquid Natural rubber Poly- chloroprene (Neoprene) Butyl rubber Butadiene- styrene rubber (7L5% styrene) Butadiene- acrylonitrile rubber (18% acrylo- nitrile) Silicone rubber (dimethyl siloxane)... 

Liquid rubber is defined in the UNIDO report s a class of elastomers or elastomer precussors that can be poured or pumped at temperature below lOO C without the assistance of an external medium. Frequently liquid natural rubber (LNR) can be defined as a form of NR with a similar microstructure but shorter polymeric chain and with molecular weight, Mw, lower than 10. A much shorter polymeric chain LNR is more open to structural design such as... 

Table 4 The potential commercial applications of Liquid Natural Rubber...

UNIDO (1986). Development of Liquid Natural Rubber. Project No UF/GLO/81 /059, IRCA... 

Among the polymer electrolytes obtained from natural polymers, Klink-lai et reported ionic conductivity and NMR spectroscopy of polymer electrolytes formed by the mixture of liquid epoxidized natural rubber with Uthium salts. The authors discussed the correlation between the spin-lattice relaxation times with the solubility of the different lithium salts in the deprotonized liquid rubber. Based on the NMR chemical shift and the resonance half-width and the spin-lattice relaxation times results they concluded that lithium bis(trifiuoro methane sulfonyl)imide is a suitable salt for forming polymer electrolytes with deprotonized liquid natural rubber. 

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