Acid effect in grafting

Acid Effect in Grafting With Isomeric Alcohols. With the isomeric propanols and butanols, some unexpected results were obtained both in the presence and absence of acid (Table II). 

This viscosity increase would then lead to an enhanced Trommsdorff peak as observed in the presence of acid. In reverse, the acid effect in grafting may well be used to substantiate the proposed viscosity explanation for the mechanism of the Trommsdorff effect in general polymerization reactions. 

Acid and PFM Additive Effects in Grafting Initiated by Ionising RadiatioTT... 

Acid Effects in the Radiation Grafting of Monomers to Polymers, Particularly Polyethylene... 

TABLE I. Acid Effect in Radiation Grafting to Polyethylene using Styrene in Low Molecular Weight Alcohols.a... 

TABLE VI. Acid Effect in Radiation Grafting using Styrene in DMF, DMSO, Acetone, Dioxan, Chloroform and Hexane.0 ... 

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. 

Further work (10) with acid effects in the radiolysis of binary mixtures such as benzene-methanol and pyridine-methanol indicates that the acid phenomenon is more complicated than the simple H atom model originally developed ( ). These more recent experiments (10) show that whilst increased hydrogen atom yields in the presence of acid enhance the overall grafting yield, other mechanisms also contribute to this acid effect. Thus the acid stability of intermediate radicals (I-III) and also analogous species involving the trunk polymer are important. With radicals (I-III), at low styrene concentrations in methanol, these intermediates (MR-) will predominantly react with other available... 

Acid Effect in UV- and Radiation-Induced Grafting of Styrene to Cellulose... 

In the present work, further mechanistic data for the acid effect in both UV and gamma radiation systems are reported, particularly molecular weight studies on the species present in the grafting solutions. The significance of these acid effects in possible commercial applications of the resulting copolymers of cellulose is also briefly mentioned. 

It is thus possible to investigate the conditions under which common intermediates may exist in both grafting and homopolymerisation processes. The results in the following Tables I -VIII thus concern acid effects in the radiation homopolymerisation of styrene in dioxan. 

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... 

Acid Effects in UV Grafting of Styrene. Since styrene is the basic monomer used in the comonomer grafting techniques to be discussed, the UV copolymerization properties of this monomer, particularly in the... 

Acid Effects in UV Comonomer Grafting of Methyl Methacrylate. The UV grafting of methyl methacrylate dissolved in methanol to cellulose is complicated by the degree to which competing homopolymerization occurs. The problem most often encountered is the solidification... 

Acid Effects in UV Comonomer Grafting of Ethyl Acetate. The... 

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