Styrene to polyethylene film

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

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).

Grafting Styrene to Polyethylene Film Initiated by Ionising Radiation... 

Fig 6. Effect of dose rate on the efficiency of grafting styrene to polyethylene film in methanol in the presence of acid (H SO, 0.2M). Total dose, 2.3 x 10 rad. 

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. 

The optimum in the copolymerisation process occurs at 50% monomer concentration with both additives. The behaviour of sulfuric acid in these reactions is representative of the most reactive of the mineral acids (12). A comparison of TMPTA with H SO (0.2 M) also indicates that similar trends in enhancement in radiation grafting to polyethylene film are observed with both additives (Table III). Again, when polypropylene film is used as backbone polymer (Table IV), acid and DVB show similar increases in grafting yield with styrene in methanol, however in this system, it is interesting to note that the concentration of monomer at the position of the Trommsdorff peak does not vary for neutral and acidified grafting solutions but changes from 30% to 35% when DVB is additive. 

Styrene in methanol radiation grafted to polyethylene film (0.12 mm) at 4.1x10 rad/hr to dose of 2.4x10 rad in air. 

Table VII. Comparison of Acid with Polyfunctlonal Monomers as Additives for Enhancing UV and Ionizing Radiation Grafting of Styrene In Methanol to Polyethylene Film...

Table 3. Effect of Sulfuric Acid on Radiation Grafting of Styrene in Methanol to Polyethylene Film at Dose Rates of 10,000 and 21,000 Rad/hr ...

Fig 4. Effect of dose rate (rad/hr) on grafting of styrene in methanol in neutral and acid solution to polyethylene films at total dose of 2.3 x 10 rad. 

Blends of butadiene-styrene block polymers with polyolefins, particularly polypropylene are mentioned in literature to improve the impact strength of the latter. Since similar improvements can be realized from the use of polyolefin block polymers, the blends have not gained much recognition. However, butadiene-styrene radial teleblock polymers are blended into polyethylene film, to increase the tear resistance and tensile impact. ... 

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). 

Also it is possible to swell e.g. a polyethylene film in a mixture of styrene, divinylbenzene and a catalyst and after that to polymerize in the film (50, 58). 

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 ... 

Low absorptive capacity primary foam dressings have been produced from a carboxylated styrene butadiene rubber latex foam. The foam is bonded to a non-woven fabric coated with a polyethylene film which has been vacuum ruptured. The basic foam is naturally... 

Inclusion of sulfuric acid (0.2M) in the styrene-methanol grafting solution gives an enhancement in radiation grafting with polyethylene film similar to that obtained with DVB (Table II). 

Monomers which have also been demonstrated to have been grafted to polyethylene and polypropylene film by this process include styrene and various acrylated esters, mixtures of acrylated esters, and acrylonitrile. The application of this technology to improving the barrier properties of films is discussed. Some initial data on the O2 barrier, fragrance/aroma, and haze performance of these graft modified films indicate substantial Improvement and place them in the high barrier range where dry Oo permeabilities of less than 1 cc/100 ln /24 hrs. are ootained. 

Alkali and acid treatments have also been used to modify surface properties of polymers sulfonated polyethylene films treated first with ethylenediamine and then with a terpolymer of vinyhdene chloride, acrylonitrile, and acrylic acid exhibited better clarity and scuff resistance and reduced permeabihty. Permanently amber-colored polyethylene containers suitable for storing light-sensitive compoimds have been produced by treating fluorosulfonated polyethylene with alkali. Poly(ethylene terephthalate) dipped into trichloroacetic/chromic acid mixture has improved adhesion to polyethylene and nylons. Antifogging lenses have been prepared by exposing polystyrene films to sulfonating conditions. Acid and alkali surface treatments have also been used to produce desired properties in polymethylmethacrylates, polyacrylonitrile, styrene-butadiene resins, polyisobutylene, and natural rubber. Surface halogenation of the diene polymers natural rubber and polyisobutylene resulted in increased adhesion to polar surfaces. 

---