Grafted polyethylene films

Berg, R. H. Almdal, K. Pedersen, W. B. Holm, A. Tam, J. P Merrifield, R. B. Long-Chain Polystyrene-Grafted Polyethylene Film Matrix A New Support for Solid-Phase Peptide Synthesis, J. Am. Chem. Soc. 1989, 777, 8024. 

Besides classical resin beads, other polymeric carriers were also used for the synthesis ofpeptide libraries in various formats. Poly aery late-grafted polypropylene pins were used for the synthesis of the first combinatorial chemical library [1,2], This type of support continues to be heavily used in multiple peptide [27] and non-peptide [28] library synthesis. Cellulose paper, originally used by Frank et al. as a solid-phase support for oligodeoxy-ribonucleotide synthesis [29], has also been used as the support for multiple SPOT synthesis of peptide libraries [30,31], Polystyrene-grafted polyethylene film (PS-PE) may also be used in combinatorial peptide library synthesis [32], The specific feature of the membrane type of carrier is its dividability. This feature has been used for the synthesis of libraries with a nonstatistical distribution of library members, where no compound is missing and none is represented more than once [33],... 

A peptide library can be synthesized using the SPOT synthesis technique to form a low-density peptide spot array (e.g., 25 spots/cm ). In this method, different peptides are synthesized in situ as low-density arrays on cellulose membrane or paper (8). The volume of Fmoc-amino acids and coupling reagents dispensed creates a specific SPOT size that determines both the scale of reaction and the absolute number of peptides that can be arranged on an area of a membrane. Cotton (another form of cellulose) and polystyrene-grafted polyethylene film segments also have been used as solid supports. Recently, polymeric membranes that are chemically, mechanically, and thermally more stable have been developed, which include hydroxy-functionalized PEG acrylate polypropylene membranes and an amino-functionalized ester-free PEG... 

Cotton has mechanical properties superior to paper and has been used in a similar way by Lebl.P Polystyrene-grafted polyethylene film has also been used by researchers from Rockefeller University.P l Researchers from Pfizer used material prepared from resin sandwiched in between two sheets of polypropylene mesh.P The sandwich was fused together with a polymer with a low melting point. 

Multiple peptide synthesis has also been achieved by using polystyrene-grafted polyethylene films (PS-PE) which are produced using X-ray irradiation.22 Small areas of the film (typically 1.5 x 3 cm) serve as reaction compartments where coupling can be carried out separately while washing and deblocking is carried out simultaneously. 

Kim DK, Ganesan R, Jung CH, Hwang IT, Choi JH, Kim JB, et al. Micropatterning of proteins on ion beam-induced poly(acrylic acid)-grafted polyethylene film. Polym Adv Technol 2011 22(12) 1989-92. 

Table 5. Reversible adsorption and desorption of metal ions by plasma-grafted polyethylene films...

Kondo, T., Koyama, M., Kubota, H. et al. 1998. Characteristics of acrylic acid and N-isopropylacrylamide binary monomers-grafted polyethylene film synthesized by photografting. J Appl Polym Sci. 67 2057-2064. 

KON 98] Kondo T., Koyama M., Kubota H. et al. Characteristics of acrylicacid and N-isopropylacrylamidebinarymonomers-grafted polyethylene film synthesized by photografting , Journal of AppliedPolymer Science, vol. 67, pp. 2057-2064, 1998. 

Advanced development of ion-selective films has been attempted by radiation grafting of methacrylic acid on polyethylene films, and combination of this with cellophane are also being tested. Polyamide fleece impregnated with regenerated cellulose, is another option for zinc-silver oxide batteries. 

Figure 5. ESCA spectra of polyethylene film (PE) and polyethylene fiber (split film PE-F) after grafting for 2 min. with the vapor phase method.

Polyethylene film kinetics of surface grafting, 174/ surface grafting, 178/... 

Table I. Synergistic Effect of Acid and TMPTA as Additives in Grafting Styrene to Polyethylene Film Initiated by Ion is ing Radiation8 ...

The parameters which predominantly influence the acid effect in radiation grafting of styrene monomer to polyethylene film are the structure of solvent, the concentration of monomer and the dose rate. Because these three variables are inter-related, it is difficult to predict, a priori, the conditions required to yield an optimum in grafting. In this respect the type of solvent used is particularly important. 

Synthesis of Hyperbranched Poly(acrylic Acid) Grafts on Polyethylene Films... 

Scheme 4 Chemistry used to prepare hyperbranched polyfacrylic acid) grafts on polyethylene film, polyethylene powder or polypropylene wafers...

A similar approach was used in grafting Cjq onto a pregenerated lithiated polyethylene surface [121]. A polyethylene film with terminal diphenylmethyl groups was deprotonated with BuLi to yield an anionic polyethylene surface that was treated with Cg0 and quenched with methanol. The incorporation at the polyethylene surface was determined by XPS, UV/Vis and fluorescence spectroscopy. This reaction also works for polyisopropene, polybutadiene [69], poly(vinylbenzyl chloride) or poly(N-vinylcarbazole) PVK [54] with BuLi or NaH as a base. Charge-transfer interactions in the soluble fullerene-PVK derivative between the positively charged carbazole and Cjq lead to an enhanced photoconductivity compared with PVK [54]. 

One of the common chemical methods for determining carbonyl compounds consists of converting them into hydrazones [7], This has been used for (1) oxycellulose [28], (2) nylon-6 and nylon-6,6 [29], (3) dehydrogenated poly (vinyl chloride) [30], (4) in irradiated polyethylene films [31], and (5) grafted polyethylene glycol [32],... 

Figure 2. Influence of preirradiation dose of polyethylene films in air on the rate of grafting observed on heating at 135°C. in acrylonitrile (2)...

The influence of the polymer structure on the irradiation grafting has been examined in the case of styrene to high pressure and low pressure polyethylene films (114). The most important factors which determine the efficiency of grafting are the degree of crystallinity, the thickness of the films and the dose rate. 

As films are used e.g. the polymerization product of ethylbenzene and divinylbenzene (33) the copolymer of styrene and butadiene (755) the copolymer of styrene and butadiene mixed with polyethylene (157) a vulcanized or cyclized copolymer of an aromatic vinylcompound and an aliphatic conjugated polyene (2). As a crack resisting matrix is mentioned the copolymer of styrene, divinylbenzene and butadiene with e.g. dioctylphthalate as a plasticizer (176). Other examples are the copolymers of unsaturated aromatic compounds and unsaturated aliphatic compounds (77) and the reaction products of polyolefines and partially polymerized styrene (174). Primary groups can be introduced also with the help of Friedel-Crafts catalyst. Ts. Kuwata and co-workers treated a film of a copolymer of styrene and butadiene with an aluminium-ether complex and ethylenedichloride (79). Afterwards they allowed the film to react with trimethylamine. Another technique is the grafting of e.g. a polyethylene film with styrene (28). 

The latter effect has not yet been investigated quantitatively. So far, only one interesting paper49 by Odian and Kruse has been reported who performed a mathematical analysis of the grafting of styrene to irradiated polyethylene films for different ratios between the diffusion and the grafting rates. For stationary graft polymerization they derived the following equation ... 

Figure 1. Effect of divinylbenzene on grafting of styrene to polyethylene film in methanol at dose rate of 4,1 X rad/h to total dose of 2,5 X 10 rad. Key O, styrene-methanol , styrene-methanol-divinylbenzene (1% v/v).

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