Styrene polymer film

Impregnation and polymerization of vinyl monomers in polymeric films. Vinyl monomers swell some kinds of polymer films styrene and divinylbenzenes swell poly(vinyl chloride) films substantially. After a polymer film such as poly(vinyl chloride) or polyethylene has been swollen in a vinyl monomer mixture containing a radical initiator, the film is covered with another film that does not swell with the vinyl monomers, e.g. cellulose film, poly(vinyl alcohol) film, and heated to polymerize the monomers in the film. Ion exchange groups are introduced into the resulting precursor membrane, for example by sulfonation, chloromethylation... 

Lamination of polymer films, both styrene-based and other polymer types, to styrene-based materials can be carried out during the extmsion process for protection or decorative purposes. For example, an acryUc film can be laminated to ABS sheet during extmsion for protection in outdoor apphcations. Multiple extmsion of styrene-based plastics with one or more other plastics has grown rapidly from the mid-1980s to the mid-1990s. 

Polymer films can be made antistatic with a-sulfonated fatty acid salts and esters [94]. For example, an antistatic additive for polypropylene manufacture can be prepared from potassium methyl a-sulfopalmitate, styrene oligomer, and 2-propanol [95]. The treatment of synthetic fibers and fabrics with a-sulfo-... 

TiCU readily functionalizes hydrophilic polymers such as poly(vinyl alcohol), m-ciesol novolac and methacrylic acid copolymers as well as moderately hydrophobic polymers such as poly(methyl methacrylate), poly(vinyl acetate), poly(benzyl methacrylate) and fully acetylated m-cresol novolac. HCI4 did not react with poly(styrene) to form etch resistant films indicating that very hydrophobic films follow a different reaction pathway. RBS analysis revealed that Ti is present only on the surface of hydrophilic and moderately hydrophobic polymer films, whereas it was found diffused through the entire thickness of the poly(styrene) films. The reaction pathways of hydrophilic and hydrophobic polymers with HCI4 are different because TiCl is hydrolysed by the surface water at the hydrophilic polymer surfaces to form an etch resistant T1O2 layer. Lack of such surface water in hydrophobic polymers explains the absence of a surface TiC>2 layer and the poor etching selectivities. 

The effect of blending LDPE with EVA or a styrene-isoprene block copolymer was investigated (178). The properties (thermal expansion coefficient. Young s modulus, thermal conductivity) of the foamed blends usually lie between the limits of the foamed constituents, although the relationship between property and blend content is not always linear. The reasons must he in the microstructure most polymer pairs are immiscible, but some such as PS/polyphenylene oxide (PPO) are miscible. Eor the immiscible blends, the majority phase tends to be continuous, but the form of the minor phase can vary. Blends of EVA and metallocene catalysed ethylene-octene copolymer have different morphologies depending on the EVA content (5). With 25% EVA, the EVA phase appears as fine spherical inclusions in the LDPE matrix. The results of these experiments on polymer films will apply to foams made from the same polymers. 

In order to access a wider variety of monomers, higher temperatures were necessary. Using an aluminum channel capped on one wall with a Kapton film, styrene, as well as several acrylates and methacrylates, were polymerized. Furthermore, block copolymers were also prepared from these more widely used polymers, and the devices were integrated with characterization techniques as described below... 

Latexes are usually copolymer systems of two or more monomers, and their total solids content, including polymers, emulsifiers, stabilizers etc. is 40-50% by mass. Most commercially available polymer latexes are based on elastomeric and thermoplastic polymers which form continuous polymer films when dried [88]. The major types of latexes include styrene-butadiene rubber (SBR), ethylene vinyl acetate (EVA), polyacrylic ester (PAE) and epoxy resin (EP) which are available both as emulsions and redispersible powders. They are widely used for bridge deck overlays and patching, as adhesives, and integral waterproofers. A brief description of the main types in current use is as follows [87]. 

Knoll and coworkers were the first to synthesize polymer brushes from SAM-coated silicon wafers via a photoinitiation strategy [37-39]. They used an AIBN type initiator that was developed by Riihe. In particular, a chlorosi-lane terminus was used to form a covalent bond to the native oxide surface of the silicon this was followed by irradiation at 350 nm in the presence of styrene to yield a PS brush (Fig. 4). They were able to write patterns by irradiating through a mask to activate the surface-bound initiators. Alternatively, they synthesized a polymer film and then used deep UV ablation through masks to remove some of the polymer in the irradiated regions. By... 

It is interesting to compare the rapid growth from the tertiary amines with that of more traditional AIBN-type initiators. For instance. Fig. 8c represents the polymerization of styrene from SAMs of (24) on gold. The amino initiator yields much thicker films in about half the time. The rate of polymer film growth is important in manufacturing processes and it is usually desirable to minimize the UV exposure time. Partially for this reason, Riihe... 

A number of the mechanistic features proposed by Williams and Hayes were incorporated into a theoretical model developed by Denaro et al. to explain the kinetics of styrene polymerization in a 2 MHz discharge. Initiation was proposed to proceed through the collision of electrons with the polymer film... 

The use of a protective polymer film as barrier has been proposed. This barrier consists essentially of a thermoplastic poly(ester) resin, which is a homopolymer or copolymer adduct of an aromatic dicarb-oxylic acid in an active hydrogen-containing material. However, this poly(ester) resin copolymer has a poor compatibility with styrene resins. Thus, the protective polymer film lacks the desired regrind capability. 

Polymer films can also be electropolymerized directly onto the electrode surface. For example, Abruna et al. have shown that vinylpyridine and vinyl-bipyridine complexes of various metal ions can be electropolymerized to yield polymer films on the electrode surface that contain the electroactive metal complex (see Table 13.2) [27]. The electronically conductive polymers (Table 13.2) can also be electrosynthesized from the corresponding monomer. Again, a polymer film that coats the electrode surface is obtained [25]. Electropolymerized films have also been obtained from styrenic, phenolic, and vinyl monomers. 

Miyaki and Fujimoto and co-workers [16,17] have obtained an even finer distribution of fixed charge groups by casting films from multicomponent block copolymers such as poly(isoprene- >-styrene- >-butadiene- >-(4-vinyl benzyl)dime-thylamine- Msoprene). These films show a very regular domain structure with a 200-500 A spacing. After casting the polymer film, the (4-vinyl benzyl) dimethy-lamine blocks were quatemarized with methyl iodide vapor, and the styrene blocks were sulfonated with chlorosulfuric acid. 

Kapui et al. prepared a novel type of polypyrrole films [168]. The film was impregnated by spherical styrene-methacrylic acid block copolymer micelles with a hydrophobic core of 18 nm and a hydrophilic corona of 100 nm. The properties of the micelle-doped polypyrrole films were investigated by cyclic voltammetry and SECM. It was found that the self-assembled block copolymer micelles in polypyrrole behave as polyanions and the charge compensation by cations has been identified during electrochemical switching of the polymer films. 

Figure 12.7 Polymer film thickness growth in a styrene/N2 system as a function of discharge time for two different mixing method of gases the upper curve for the method A, the lower curve for the method B.

H.P. Brack, H.G. Buhrer, L. Bonorand, and G.G. Scherer. Grafting of pre-irradiated poly(ethylene-alt-tetrafluoroethylene) films with styrene Influence of base polymer film properties and processing parameters. Journal of Materials Chemistry 10, 1795-1803 2000. 

Summary AIBN-type radical polymerization initiators have been grafted onto poly-ciystalline titanium surfaces allowing synthesis of polymer films covalently bound to the surfaces. Vinylic monomers such as styrene, methyl methacrylate, and 4-chloromethyl-styrene have been used the pendant benzyl chloride moiety present at the outer surface of the polymer film obtained fi om the latter monomer has allowed further functionalization of the system. In the case of polystyrene films on Ti, molecular weights of the polymer have been estimated to be A/w == 25 000 A/ = 10 000 (Pd = 2.5). 

In the next step, we carried out the polymerization experiments using three vinylic monomers, i.e. styrene, methyl methacrylate, and 4-chloromethyl-styrene, by dipping the appropriate titanium plates into deoxygenated monomer/toluene solutions (1 2, v/v) at 90 °C for 24 h. Interestingly, grafted initiators ACTP and ACTU gave very comparable polymer films from the two styrene monomers, whereas polymerization of methyl methacrylate was found to be significantly better on Ti-ACTP than on Ti-ACTU. 

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