The semiclassical approximation is extended to the case of ionisation of atoms by relativistic charged particles. The theory is formulated both for a relativistic and a non-relativistic electron description. For total cross sections the theory is shown to be equivalent to the relativistic plane-wave Born approximation. Numerical results for the impact parameter distribution of the ionisation probability for the K shell are given.
Modified glass fibers, containing unsaturated hydrocarbon surface groups, were prepared by a hydrothermal treatment, with allylglycidylether in excess as reagent. Graft polymerization of the treated glass fiber with styrene and methylmethacrylate was carried out in sealed tubes, under nitrogen, using benzoyl peroxide (BPO) and cumene hydroperoxide (CHPO) as initiators. When BPO was used as the initiator, the grafting efficiency was extremely low, but the graft copolymerization behavior was similar to that of usual organic polymers. With CHPO, both grafting ratio and grafting efficiency were very high. Various properties of composite materials containing grafted glass cloth were studied. Flexural strength, flexural modulus, and interlaminar shear strength increased proportionally to the increase of the grafting ratio; the same values were decreased only in a small extent after the boiling test.
Graft polymerization was carried out on carbon fibers subjected to various types of oxidation treatment and on acrylate (methyl, ethyl, and n‐butyl) with benzene solvent and mainly benzoyl peroxide as initiator according to the nitrogen‐displacement sealed‐tube polymerization method. In comparison with carbon fibers subjected to air oxidation treatment, carbon fibers subjected to nitric acid oxidation treatment showed easier graft polymerization, and grafting became easier with increasing degree of nitric acid oxidation. The following relationship is established between the graft reaction ratio (a) and the polymerization time (t): da/dt = K(100−a). For graft polymerization with lauroyl peroxide (LPO), benzoyl peroxide (BPO), and α,α′‐azobisisobutyronitrile (AIBN) as initiator, LPO showed the largest transfer reaction constant, followed by BPO; AIBN showed the smallest value. Grafting showed a tendency to become easier for monomers with a larger displacement radical group. For the graft polymerization reported in this article, it was believed that the affinity between carbon fibers subjected to oxidation treatment and to monomer influenced the result. For graft polymerization using acrylic acid as the comonomer, percent grafting increased notably. It is believed that, in this, in this case, apparent grafting by dipole‐dipole interaction of the COOH group of the carbon fiber subjected to oxidation treatment and the COOH group of the polymer occurs according to the theory of Riess et al. Tensile strength and breaking elongation of graft carbon fibers showed a tendency to increase with an increase in percent grafting, whereas Young's modulus showed a tendency to decrease. The contact angle with water showed a tendency to increase with increasing percent, whereas the contact angle with ethylene glycol and phenylglycidilethyl showed a tendency to decreasing percent grafting.
SynopsisModified glass fibers, containing unsaturated hydrocarbon surface groups, were prepared by a hydrothermal treatment, with allylglycidylether in excess as reagent. Graft polymerization of the treated glass fiber with styrene and methylmethacrylate was carried out in sealed tubes, under nitrogen, using benzoyl peroxide (BPO) and cumene hydroperoxide (CHPO) as initiators. When BPO was used as the initiator, the grafting efficiency was extremely low, but the graft copolymerization behavior was similar to tbat of usual organic polymers. With CHPO, both grafting ratio and grafting efficiency were very high. Various properties of composite materials containing grafted glass cloth were studied. Flexural strength, flexural modulus, and interlaminar shear strength increased proportionally to the increase of the grafting ratio; the same values were decreased only in a small extent after the boiling test.
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