Vinyl benzyl chloride

Functionalization of these reactive anionic chain ends can be achieved by a variety of methods all based on the general concepts of carbanion chemistry. For example, reaction with C02 or succinnic anhydride leads to the carboxy terminated derivatives [10], while hydroxy-terminated polymers can be easily obtained by reaction with ethylene oxide (Scheme 3) [11]. In select functionalization reactions, such as alkylation with p-vinyl benzyl chloride, the nucleophilicity of the carbanionic species may be necessary and this can be achieved by reaction of the chain end with 1,1-diphenylethene followed by functionalization [12,13]. 

The chloromethylated polystyrene is usually obtained by chloromethylation of polystyrene (Eq. 9-38), although polymerization of p-vinyl benzyl chloride has also been used [Arshady et al., 1976]. A less desirable variation of this approach is the physical entrapment of a catalyst, substrate, or reagent within a polymer. 

Dispersed phase polymerisation of HIPEs has also been used to prepare polymer-supported quaternary onium phase transfer catalysts [162]. One strategy involved the polymerisation of a concentrated emulsion of vinyl benzyl chloride (VBC) in water and subsequent quaternisation of the polymer resin with tertiary amines and phosphines (Fig. 22). 

Another chlorinated derivative of polystyrene is poly(vinyl benzyl chloride), CAS 121961-20-4, with the formula [-CH2CH(C6H4CH2CI)-]n. This polymer is a mixture of 3-and 4- isomers in 60/40 ratio. The results for a Py-GC/MS analysis of a sample with M = 100,000 are shown in Figure 6.4.2. The pyrolysis was done at 600° C in He at a heating rate of 20° C/msec. with 10 sec. THT. The separation was done similarly to that for other polymers given previously as examples, on a Carbowax column with the GC starting at 40° C with a ramp of 2° C/min. up to 240° C and a final oven time of 20 min. (see Table 4.2.2). 

Figure 6.4.2. Result for a Py-GC/MS analysis ofpoly(vinyl benzyl chloride) M = 100,000 (mixture of 3-and 4- isomers in 60/40 ratio). Pyrolysis done on 0.4 mg material at 60(f C, with the separation on a Carbowax type column.

The pyrogram of poly(vinyl benzyl chloride) is very simiiar to that of other polystyrene related polymers. The presence of two main monomer peaks in the pyrogram is caused by the fact that the polymer is a mixture of 3 and 4 substituted polymer. The peak area ratios of several 3- and 4-isomers is around 60/40. For example, for 1-(chloromethyl)-3-methylbenzene and 1-(chloromethyl)-4-methylbenzene the ratio is 59.9/40.1, for 1-(chloromethyl)-3-ethylbenzene and 1 -(chloromethyl)-4-ethylbenzene the ratio is... 

Hyperbranched polymers may be prepared by the self-condensing vinyl polymerization (SCVP) [257] of AB star monomers by a controlled free radical process, such as ATRP [258]. The result, under certain conditions, is a highly branched, soluble polymer that contains one double bond and, in the absence of irreversible termination, a large quantity of halogen end groups equal to the degree of polymerization which can be further functionalized [87] (Fig.35). Two examples explored in detail by ATRP are vinyl benzyl chloride (VBC, p-chlo-romethylstyrene) [258] and 2-(2-bromopropionyloxy)ethyl acrylate (BPEA) [259-261] both depicted in Fig. 35. Several other (meth)acrylates with either 2-... 

Fig- 35. Illustration of a hyperbranched polymer with halogen chain ends (X), 2-(2-bromo-propionyloxy) ethyl acrylate (BPEA), and vinyl benzyl chloride (VBC)... 

The most common example of macromonomers in this category are polyethylene oxide and propylene oxide. From their method of preparation they have one or two end -OH groups which can be used for post-polymerization reactions. Acryloylchloride, methacryloylchloride, p-vinyl benzyl chloride, and iso-cyanatomethylmethacrylate are some of the reagents reacted with PEO or poly(propylene oxide) (PPO) to prepare macromonomers. A few of these reactions [195,196] are presented in the following schemes (Scheme 61). 

This synthetic method has two steps the first step involves synthesising the polymer and the second includes modification with active groups. Some monomers generally used to form the backbone of homopolymers or copolymers include vinyl benzyl chloride, methyl methacrylate, 2-chloroethyl vinyl ether, vinyl alcohol and maleic anhydride. The polymers are then activated by anchoring antimicrobial groups, such as phosphonium salts, ammonium salts or phenol groups, via quaternisation, chloride substitution or anhydride hydrolysis. 

Addition of 2.8 mL (20 mmol) vinyl benzyl chloride to the polymer and stirring for 24 h at room temperature. 

Kong et al functionalized CNTs with HPs by SCVP of vinyl benzyl chloride (VBC) in toluene at 110-130 °C for 24-48 h via ATRP using CuBr/ PMDETA or CuCl/bpy as the catalyst, and the grafted content of hyperbranched polystyrene reached 50 wt%. 

It should be noted that vinyl benzyl chloride monomer is available commercially. It is therefore possible to simply prepare the chloromethylated polystyrene or copolymers from the monomer without the chloromethylation reactions. 

To understand the reasons for different predictions of different methods, Li et al. [83] measured the adhesion between a variety of polymers with well-controlled backbone chemistry These polymers include poly (4-methyl 1-pentene) [TPX], poly(vinyl cyclohexane) [PVCH], polystyrene [PS], poly(methyl methacrylate) [PMMA], and poly(2-vinyl pyridine) [PVP], poly(4-tert-butyl styrene) [PtBS], poly(acrylonitrile) [PAN], poly(p-phenyl styrene) [PPPS], poly(vinyl benzyl chloride) [PVCB]. It may be noted that, among the polymers listed above, TPX and PVCH are purely dispersive in nature. PS is predominantly dispersive with some dipole-induced dipole interactions. 

PA-66 (2.7 parts)/EA-BA-vinyl benzyl chloride copolymer (0.9 parts 0.23-0.33 % reactive chloride) SSE at 280 °C/multiple pass extrusion/ mechanical properties/aiso used vinyl chloroacetate as reactive chloride source Moncur 1982... 

Recently Asami et al. improved the method of preparing (p-vinylbenzyl) polystyrene macromer by direct reaction of living polystyrene with p-vinyl-benzyl chloride, in the presence of tetrahydrofuran without using a capping agent. 

Some of the earlier work in PS-MMT nanocomposites investigated the modification of MMT with reactive cations consisting of a styrene group attached to the ammonium ion (structure 36, Table 13.2) [41, 43-45, 77]. Khalil modified sodium MMT with 4-vinyl benzyl chloride and used this to form styrene and acrylonitrile-styrene copolymers [43, 44], Akelah et al. [45, 77] also investigated vinylbenzyl... 

If the resin has microbeads of crosslinked polyacrylic acid embedded in a matrix of poly(vinyl benzyl chloride) aminated with dimethyl amine, the amphoteric IPN can absorb salts from water in a thermally reversible manner ... 

Macromonomers have been also prepared by post-polymerization reactions. Poly(ethylene oxide) (PEO) or poly(propylene oxide) (PPO) has one or two —OH end groups depending on the method of their preparation. These —OH groups may react with (meth)acryloyl chloride, p-vinyl benzyl chloride, norbomenyl chloride, 4-vinyl benzoyl chloride, etc. for the synthesis of the corresponding macromonomers (109,110) (eq. 33). 

Preparation of hyperbranched polymers using ATRP involves self-condensing vinyl polymerization (SCVP) (Frechet et al., 1995) of AB monomers, which contain two active species, viz., the double bond A group (polymerizable) and the initiating site B. Two main examples explored in detail within the context of ATRP are p-chloromethyl styrene or vinyl benzyl chloride (VBC) and 2-(2-bromopro-pionyloxy) ethyl acrylate (BPEA) (Fig. 11.30). Several other (meth)acrylates with either 2-bromopropionate or 2-bromoisobntyrate gronps have also been used. 

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