Silanes grafting

Gross-Linking. A variety of PE resins, after their synthesis, can be modified by cross-linking with peroxides, hydrolysis of silane-grafted polymers, ionic bonding of chain carboxyl groups (ionomers), chlorination, graft copolymerization, hydrolysis of vinyl acetate copolymers, and other reactions. 

Patent Number US 6103775 A1 20000815 SILANE-GRAFTED MATERIALS FOR SOLID AND FOAM APPLICATIONS... 

Patent Number US 5859076 A 19990112 OPEN CELL FOAMED ARTICLES INCLUDING SILANE-GRAFTED POLYOLEFIN RESINS... 

Describes open cell foamed articles including silane-grafted single-site initiated polyolefin resins. The olefin polymer resin can be a polyethylene, a copolymer of ethylene, a C3-C20 alpha-olefin, or a copolymer of ethylene, a C3-20 alpha-olefin and a C4-C20 diene. The open cell foamed articles have good cushioning properties and can be non-allergenic. 

This is a blend of LDPE, which generally has a density between 0.91 and about 0.93 g/cu.cm. and a melt index greater than 1 and a silane-grafted single-site initiated polyolefin, which is generally a copolymer of ethylene and a C3 to C20 alpha-olefm having a density between about 0.86 and 0.96 g/cu.cm. and a MWD between about 1.5 and 3.5. 

Shieh Y-T, Tsai T-H (1998) Silane grafting reactions of low-density polyethylene. J Appl Poly Sci 69(2) 255-261... 

ShenJ, Ye N (2001) Study on reaction kinetics of silane grafted HDPE and LLDP. Hecheng E Shuzhi Ji Suliao 18(3) 9—12... 

Also compatibilizers can be applied for two-phase systems in order to reduce the phase size and improve the properties. This method has been successfully applied in an EPDM-silicone system using a silane grafted ethylene-propylene rubber (EPR) [5]. However, the combination possibilities of poly(organosiloxane)s with thermoplastics and elastomers are still limited to special systems. 

Fig. 2 Scanning electron microscopy images (A) pure LDPE (B) silane grafted and cured in hot water and (C) electron beam irradiated.

Fig. 3 Differential scanning calorimetry profiles (A) electron beam irradiation and (B) silane grafting and curing in hot water.

The attachment of trialkoxysilane functionality to polyolefins (HDPE, LDPE, PP) though grafting of vinylsilanes e.g. 40, 41) or silane functional acrylates e.g. 42) has been widely studied. The principal application of these materials is the preparation of moisture curable crosslinked polyolefins that arc widely used in the cable industry. Silane treatment has also been used for surface modification of polyolefins " and silane grafted polyolefins might also serve as precursors to graft copolymers. 

Porous materials obtained via silane grafting may face problems of nonuniform distribution of the functionalities. Pore blocking can occur if the grafted silanes accumulate at the pore entrances. Also, unwanted silane oligomerization can occur, especially in the presence of water. 

The FEMTO ST Institute [Pichonat et al.] demonstrated an alternative solution which does not use an ionomer for the proton exchange membrane but consists in a porous silicon membrane with a proton conducting silane grafted on the pores walls [16,17]. A demonstrated fuel cell with dimensions of 8 x 8 mm and an active area of 7 mm with this membrane achieved a maximum power density of 58 mW cm at room temperature with H., as fuel. 

POEs have been used in both plastic rmd rubber applications. These elastomeric polyethylenes have ability to be cross-linked via peroxide, irradiation, and moisture (if silane grafted). Potential applications include tubing, impact modifiers, low-voltage cable insulation, elastic films, foams, shoe soles, belts, automotive hoses, medical applications, gasket seals, and other electrical applications. 

A. Sharif-Pakdaman, J. Morshedian, Y. Jahani, Effect of oiganoclay and silane grafting of polyethylene on morphology, barrierity, and theological properties of HDPE/PA6 blends. J. Appl. Polym. Sci. 127, 1211-1220 (2013)... 

PMMA expandable graphite composites Silane grafted on polymer LOl and TGA used to calculate flame retardance and thermal stability [41]... 

Fig. 18. Crosslinking step of silane-grafted HFFR compound.

Functionalization of the polymer has been widely employed in binary nanocomposites to improve the polymer/filler interactions and thus maximize the load transfer. Functionalization also serves to enhance the compatibility between the two components of polymer blend. Many grades of functionalized polymers are now available, including maleated grades and silane-grafted polymers. Examples of functionalized matrices studied in ternary nanocomposite studies include PP-g-MA [41], PP-g-VTEOS [27] and examples of functionalized elastomers include SEBS-g-MA [8,49,65], EPR-g-MA [19,44,65], POE-g-MA [75], and EPDM- -MA [64]. It is also important to note that only nonpolar matrices and elastomers require functionalization, as opposed to polar polymers like PA6, which present natural interactions with polar fillers such as silica particles and clay platelets. 

Bailly, M. and Kontopoulou, M. 2009. Preparation and characterization of thermoplastic olefin/ nanosilica composites using a silane-grafted pol5 ropylene matrix. Polymer 50 2472-2480. 

V inyltrimethoxy silane-grafted PE CORI Moisture tm>ss-linking Ultsch and Fritz 1990... 

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