Groups siloxane moieties

A non-woven web having antimicrobial properties is made from a melt extmdable composition, which contains a polyolefin and an antimicrobial siloxane quaternary ammonium salt, which may be a trisiloxane having a pendent quatemaiy ammonium group and a molec.wt. of from about 600 to 1,700 or an ABA-type siloxane having a polydispersity of up to about 3.0 and a weight-average molec.wt. of from about 800 to 2,000 in which a central siloxane moiety is terminated at each end by a quatemaiy ammonium salt group. The anion can be any anion, which does not adversely affect the thermal stability of the salt. 

Silicone polyethers are non-ionic in nature, and have both a hydrophilic part (low molecular weight polymer of ethylene oxide or propylene oxide or both) and a hydrophobic part (the methylated siloxane moiety). The polyether groups are either ethylene oxide or propylene oxide, and are attached to a side chain of the siloxane backbone through a hydrosilylation or condensation process. They can form a rake-like, comb structure, or linear structure. Silicone polyethers are stable up to 160-180 degrees Celsius. There is a great degree of flexibility in designing these types of polymers. A very wide variety of co-polymers is possible when the two chemistries are combined. 

The adverse effect of the hydrophilic silica was attributed to the condensation reaction of surface silanol groups on the silica and phenylsilane moieties on the polymer backbone. This results in increased cross-linking via formation of siloxane bonds between the polymer and silica. 

The selective dense layer of hydrophilic membranes is made from different polymers with a high affinity for water. These polymers contain ions, oxygen functions like hydroxyl, ester, ether or carboxylic moieties, or nitrogen as imino or imi-do groups. Preferred hydropilic polymers are polyvinylalcohol (PVA) [32], poly-imides, cellulose acetate (CA) or natural polymers like chitosan [33] or alginates. Organophilic membranes usually consist of crosslinked silicones, mostly polydimethyl siloxane (PDMS) or polymethyl octyl siloxane (POMS). 

A series of cyclopentadienyhnolybdenum complexes containing a siloxane functional group, either directly attached to the metal center or to the cy-clopentadienyl moiety, have recently been described and tested imder homogeneous conditions [41], These complexes have been successfully grafted onto MCM-41 and MCM-48 [19,42] (Scheme 5). 

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