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Surface friction plays an important role in influencing the stress field development during scratch process, thus, scratch-induced deformation mechanisms. In this study, three-dimensional finite element method (FEM) parametric study was performed along with experimental validation to investigate the effect of surface friction on scratch-induced deformation and its correlation with the constitutive behavior of polymers. As scratch depth and shoulder height are the key parameters for causing scratch visibility, the focus is to investigate the effect of surface friction on these two scratch-induced deformation features and how the surface friction effect can be altered by varying the constitutive parameters. The FEM findings and experimental observations indicate that onset of groove formation during the scratch process is strongly influenced by yield stress and coefficient of surface friction. Also, the relative frictional effect on scratch-induced deformation becomes minimal if the post-yielding strain hardening slope of the polymer is high. POLYM. ENG. SCI., 53: 1405-1413, 2013. © 2012 Society of Plastics Engineers, INTRODUCTION Scratch research in thermoplastics has drawn significant attention in recent years due to its relevance in high-gloss plastics that demand aesthetic appearance. A popular method to evaluate polymer scratch [...]

Fundamental understanding of the scratch behavior of styrene-acrylonitrile (SAN) random copolymers with variation in acrylonitrile (AN) content and molecular weight (MW) is pursued using the methodology outlined in ASTM D7027-05/ISO [...]

Research has been conducted on the phosphorus compounds. The behavior of these compounds in the superacidic system has been investigated via isolation of Br (sub)3 POH (super)+ AsF (sub)6 (super)- salts and the results of their characterization by X-ray diffraction and NMR and vibrational spectroscopy are presented.

This article describes the synthesis of some new perfluoro-alkyl-substituted tertiary oxonium ions and the effect of perfluoroalkyl substitution in the structure of the ions. Data show that replacement of one methyl group with trifluoromethyl group enhances the O-CH(sub)3 bond lengths by 0.037 angstrom and the sum of the C-O-C bond angles by approximately 4.5 degrees.

This article describes synthesis and structural aspects of a 7-membered polybromide anion, tetraphenylphosphonium triiodotetrabromide. The compound is prepared from tetraphenylphosphonium bromide and iodine monobromide, which exhibits a triclinic crystal structure.

Research is presented describing the geometric structure of perfluoro-N,N-dimethylformamide using quantum chemical calculations and gas electron diffraction.

Trithiosulfonium in cations of ((RS)3S)+ can be synthesized under conditions of heterogeneous reaction.

Research has been conducted on the polymeric arsenic and antimony fluoro anion conformations. The use of X-ray studies to characterize the anions is described.

Research has been conducted on the (trifluoromethyl)iodine dichloride. The reaction of this compound with (trifluoromethyl)iodine chloride fluoride is described.

The halogenated carboxonium salts were isolated for the first time. Addition of dichloromethylmethylether to the superacidic media HF/MF5 (M = As, Sb) resulted in the production of the alkylidene oxonium salts CH3OCHX+MF6- (X = F, Cl). The salts were characterized by their low-temperature infrared and Raman spectra. The crystal structures of the hexafluoroantimonates were observed to vary in the major details.

A new synthesis of trifluoromethyl iodine diflouride (CF3IF2) is discussed. Synthesis involves the reaction of triflourimethyl iodide (CF3I) with trifluoromethyl hypochlorite (CF3OCl) at 223 K where CF3I is fluorinated by CF3OCl in an addition-elimination reaction. It is shown that CF3IF2 crystallizes in the tetragonal space group while its molecular structure is T-shaped with a disordered CF3 group.

A study is conducted on the gas phase structures of two compounds containing Si-O-N skeletons, Me3SiON(CF3)2 and Me3SiONO2. Gas phase electron diffraction analyses and the quantum chemical calculations HF/3-21G* and B3LYP/6-31G8 were used to determine geometric structures. Results show that the Si-O bond in Me3SiON(CF3)2 is oriented syn with respect to the nitrogen lone pair while the Si-O bond in Me3SiONO2 is coplanar with the nitrate group.

The reaction of phosphorous acid with superacidic system HF/SbF(sub5) forms HPF(sub4), water, and oxonium hexafluoroantimonate, crystallizing as H(sub5)0(sub2+)SbF(sub6-) in the triclinic space group P1. The crystal structure of Me(sub4)N+HPF(sub5-), formed by the reaction of HPF(sub4) with Me(sub4)N+F-, is described.

(CHsub3)sub4N+BrFsub2- was produced by thermolysis of (CHsub3)sub4N+Br(OCFsub3)sub2-, evolving Fsub2CO during decomposition. IR, Raman and super19F- and super13C- NMR were used to characterize (CHsub3)sub4N+BrFsub2-. Two infrared absorption bands were observed at 236 and 450 cmsuper -1, and one band was observed at 460 cm super -1 for BrFsub2-.

The smallest enol, vinyl alcohol Hsub2C=C-(H)OH, is shown, by microwave spectroscopy (MW) to have a synperiplanar structure, where the O-H bond eclipses the C=C double bond. GED investigations into the geometric structure of methyl trifluorivinyl ether (MTVE), CHsub3OC(F)=CFsub2 (trifluoremethoxyethene) and perfluoromethyl vinyl ether (PMVE), CFsub3OC(F)=CFsub2 (trifluoro(trifluormethoxy)ethene), were undertaken. Of particular interest was the effect of fluorination on the conformation of MVE.

(2CF3OBr*Me4N+BrF2-) is formed via an addition-elimination mechanism when trifluoromethyl hypobromite, CF3OBr, is reacted with Me4N+Br3- at -70 degrees C. An extremely unstable CF3OBr can be isolated from (2CF3OBr*Me4N+BrF2-) only by high-vacuum sublimation. A novel technique of multichannel Raman matrix spectroscopy was used to characterize CF3OBr. The vibrational spectra of the CF3OBr molecule is presented.

The reaction of H2S2 with HF-AsF5, HF-SbF5 and DF-AsF5 through protonation produces three mercaptosulfonium salts. H3S2+AsF6, H3S2+SbF6- and D3S2+AsF5 mercaptosulfonium salts are not soluble in polar solvents and in HF. The mercaptosulfonium salts decompose due to the formation of sulfur and SH3+. The bond distances of S2H3+ are equal to similar to molecules and ions but H2S2 exhibits a lengthening of the SS bond. The SSH' tortional mode for the free ion was 227 cm.-1. The impediment of tortional motion in the crystal increases the frequency and isotropic shift.

A synthetic route to the tri- and tetrasulfane compounds was developed. This route involved the condensation of CF3SSH and CF3SCl or CF3SSCl to form CF3SSSCF3 and CF3SSSSCF3, respectively. Moreover, the gas-phase structures of these sulfanes were identified by ab initio calculations at the HF/3-21G* level. X-ray crystallographic determinations for the trisulfanes RSSSR illustrated that trans and cis conformers exist in the solid depending on the Rgroups.

The two sulfur-fluorine compounds CF3SOF and CF3SF3 were found to exhibit structure-reactivity relationships. Electron diffraction analysis was used to characterize the gas-phase geometric structure of the compounds. Further examination involving sulfanes and sulfuranes showed that compounds with S-F bonds below 159.5 +/- 1.5 picometers produced adducts with Lewis acids while those with higher S-F bonds underwent ion-exchange reactions forming salts.

Research has been conducted on iodylfluoride, a halogenylfluoride in a solid state. The crystal structure of this compound has been investigated and the results are discussed.

Research discusses structural aspects of a ternary interhalogen compound with a CF(sub)3 group, which belongs to the class of (trifluoromethyl)iodine dihalides. Data reveal that the compound is very unstable in aqueous media but crystallize into an orthorhombic system.