Condensation grafting

The condensation grafting of polyethylenimine (PEI) onto poly(acrylamide-co-acryhc acid) (PAM-co-AA) was studied by FTIR spectroscopy. The reaction mechanism, which proceeded by a two-step reaction, involved the conversion of AA to acid chloride (AC) using thionyl chloride, followed by the condensation of AC onto PAM and with amine onto PEI to form the graft copolymer (125). 

The condensation grafting of polyethylenimine (PEI) onto poly(acrylamide-co-acrylic acid) (PAM-co-AA) was studied. Fourier transform infra-red spectroscopy was... 

Friedel-Grafts Reaction. Until quite recently, the manufacture of anthraquiaone ia the United States was by the Friedel-Crafts reaction benzene [71-43-2] and phthaUc anhydride [85-44-9] condense ia the preseace of anhydrous aluminum chloride to give o-benzoylbenzoic acid [85-52-9] which, on treatment with concentrated sulfuric acid, is converted iato anthraquiaoae ia high yields and purity (33). 

The third process for cross-linking is the Sioplas process developed by Dow. The first stage of this involves the grafting of an easily hydrolysable trialkoxyvinylsilane onto the polyethylene chain, the site activation having been achieved with the aid of a small amount of peroxide. The compound is then extruded onto the wire, which is collected on a drum. The drum is then exposed to hot water, or, more commonly, low-pressure steam. The water hydrolyses the alkoxy groups, which then condense to form a siloxane cross-link. ... 

FIG. 8 Phase diagram of a Langmuir monolayer in a model of grafted stiff Lennard-Jones chains. LE denotes a disordered expanded phase, LC-U a condensed phase with untilted chains, LC-NN and LC-NNN condensed phases with collective tilt towards nearest neighbors and next-nearest neighbors, respectively, and LC-mod a phase which has a superstructure and an intermediate direction of tilt. (From Stadler and Schmid [151].)... 

A novel type of grafting process was developed using a new photosensitive polymer containing vanadium (V) chelates. These polymers were generally synthesized by the condensation of a VOQ2OH complex and a hydroxy-containing polymer to produce photoactive polymer (red in color) with pendant vanadium (V) chelate. 

A similar type of condensation between a hydroxyl-containing polymer (such as secondary cellulose acetate) with VO(BrC6H4N=CHO CfiH4)2 CUVOL2CI] produces photoactive polymers [68]. When irradiated with UV light in the presence of styrene or MMA, grafted and crosslinked polymers were obtained ... 

Jacob s group reported a protocol that used mild H2O2 oxidations and MPTMS for three approaches, namely, grafted, coated, and co-condensed MCM-41 and HMS materials [58] (Figure 6.1a). The propyl spacer was stable to the oxidation conditions while sulfonic groups were generated as evidenced by NMR spectra. These materials... 

Anchored amine materials can be prepared through a number of synthetic methodologies. Because of the potential importance of these materials to organic synthesis, a ninhydrin assay was developed as a rapid laboratory determination of available surface amines. The assay agreed well with expected values for aminopropyltriethoxysilane grafted onto commercial silica. The assay also distinguished between reactive amines and protonated or poisoned surface amines on co-condensed SBA-15 materials. 

The most common method of crosslinking via short bridges is a two-step process involving trimethoxysilane, which is shown in Fig. 18.9. In the first step, we graft siloxane branches onto polyethylene with the aid of peroxy radicals. The second step consists of a condensation reaction, which occurs in the presence of hot water or steam. A siloxane bridge is created and methanol is released. 

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