Radiation grafting, of styrene

Consistent with the preceeding acid work, when TMPTA is added to the monomer solutions containing either lithium salt or urea, synergistic effects are observed for the radiation grafting of styrene to polypropylene (Table IV). Again the maximum increase in yield occurs in the monomer solution corresponding to the Trommsdorff peak. 

A theory for this acid effect has been developed essentially from the wool and cellulose work (3,4). Recently, in a brief communication, we reported analogous acid enhancement effects in the radiation grafting of monomers such as styrene in methanol to nonpolar synthetic backbone polymers like polypropylene and polyethylene (5). In the present work, detailed studies of this acid enhancement effect are discussed for the radiation grafting of styrene in various solvents to polyethylene. The results are fundamentally important since most of the experiments reported here have been performed in solvents such as the low molecular weight alcohols which, unlike cellulose and wool systems, do not swell polyethylene. 

TABLE V. Effect of Acid on Homopolymer Formation in the Radiation Grafting of Styrene in Methanol to Polyethylene.0... 

TABLE VIII. Effect of Acid in Methanol to in the Radiation Grafting of Styrene Polyethylene using Open Tubes.a ... 

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. 

Acid enhancement in the radiation grafting of styrene in methanol to cellulose (4), wool (3) and in preliminary work with the polyolefins (5 6) has been proposed as being predominantly due to such reactions. 

Rouilly, M. V., Koetz, E. R., Haas, O., Scherer, G. G. and Chapiro, A. 1993. Proton exchange membranes prepared by simultaneous radiation grafting of styrene onto Teflon-EEP films Synthesis and characterization. Journal of Membrane Science 81 89-95. 

Effect of Solvents on Radiation Grafting of Styrene to Polypropylene ... 

Finally, various attempts have been reported to interpret the kinetics of radiation grafting. The study by Mock, and Vanderkooi (123) concerned the mutual radiation grafting of styrene from the vapor phase to ethyl cellulose film at 50° C. The radical flux was determined separately using electron spin resonance. The kinetic scheme rigorously took account of the diffusion controlled nature of the reaction and the appropriate diffusion constants were separately determined (124). The value for the ratio of for the graft polymerization was determined as... 

Mock, R. A., and W. N. Vanderkooi Kinetics of mutual radiation grafting of styrene onto ethyl cellulose film. J. Polymer Sci. 56, 69 (1962). 

Molecular Weights and Average Number of Cellulose Molecules per Grafted Side Chain. Radiation Grafting of Styrene to Cellophane and Cotton (Taken from Krassig) Ref. 15. 

Mechanism of Acid Effect in Radiation Grafting. In earlier studies (13,14,15,21) on the mechanism of the acid effect on radiation grafting of styrene (MH) in dioxan or methanol (SH) to cellulose(Cell-OH)the sequence of events depicted in Equations (1) - (9) was proposed to explain the phenomenon. Thus, cellulose can undergo bond... 

A similarly poor efficiency in extraction can also be seen in Fig. 11, where the extraction result for the product obtained by the radiation grafting of styrene onto polyethylene terephthalate)(PET) fibers13 is shown. In this case the unreacted PET can be extracted after most of PS homopolymer has been extracted by repeated solution-precipitation of the sample. It should be mentioned here that the solution procedure is also necessary to extract the unreacted PET. Such a solution-precipitation procedure is also necessary for nylon-styrene13 and poly(vinyl chloride)-acrylo-nitrile14 graft products so as to remove the homopolymers to a sufficient extent. 

B. Gupta, F.N. Buchi, G.G. Scherer, and A. Chapiro. CrossUnked ion exchange membranes by radiation grafting of styrene/divinylbenzene into FEP films. Journal of Membrane Science 118, 231-238 1996. 

B. Gupta, O. Haas, and G.G. Scherer. Proton-exchange membranes by radiation grafting of styrene onto FEP films. 4. Evaluation of the states of water. Journal of Applied Polymer Science 57, 855-862 1995. 

Table Comparison of Cellulose with Polypropylene as Trunk Polymers for Acid Enhancement in Radiation Grafting of Styrene in Methanol...

T.YAMAKI, M. ASANO, Y. MAEKAWA, Y. MORITA, T. SUWA, J. CHEN, N. TSUBOKAWA, K. KOBAYASHI, H. KUBOTA, M. YOSHIDA, Radiation grafting of styrene into crosslinked PTFE films and subsequent sulfonation for fuel cell applications , Rad. Phys. Chem., 67 (2003) 403 107... 

B. Gupta, F.N. Biichi, G.G. Scherer, A. Chapiro, Cross-linked ion exchange membranes by radiation grafting of styrene/divinylbenzene into FEP films, J. Membr. Sci., 1996, 118, 231-238 B. Gupta, F.N. Biichi and G.G. Scherer, Cation exchange membranes by pre-irradiation grafting of styrene into FEP films. I. Influence of synthesis conditions,./ Polym. Sci., 1994, 32, 1931-1938. 

Table VII. Effect of Lithium Salts on Radiation Grafting of Styrene...

Effect of Acid as an Additive on UV and Radiation Grafting. Previous studies have shown that mineral acids can enhance the radiation grafting of styrene to cellulose under certain radiation conditions. W The results of analogous experiments in photografting are shown in Table III, and compared with the corresponding gamma ray data. In... 

Table IV, Effect of Acid as the Dose Is Increased on the Radiation Grafting of Styrene In Methanol to Cellulose. ...

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

Vahdat, A., Bahrami, H., Ansari, N., and F. Ziaie. 2007. Radiation grafting of styrene onto polypropylene fibres by a 10 MeV electron beam. Radiation Physics and Chemistry 76 787-793. 

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