- Email: [email protected]
ESCA studies of carbon and oxygen in carbon fibres
Abstracts of journals Prepared by P. Curtis, K. Phillips, P. Manders and 7-. Feest
CA RBON FIBRES
The dependence of the strength of carbon fibres on length Hitchon, J.W. and Phillips, D.C. Fibre Science and Technology Vol 12 No 3 (May 1979) pp 217-233 The strength distributions of Type 1 and Type 2 carbon fibres were measured at lengths of 0.5, 5, and 50mm, and the usefulness of the Weibull treatment in correlating the results tested. Weibull treatment did not accurately extrapolate strength distribution data obtained at longer lengths (50 r a m ) d o w n to fibrematrix transfer lengths (ca. 0.5 mm ): it is suggested that this failure may be due to a bimodal distribution of flaw sizes in the carbon fibre. It is suggested that modified estimates of fibre strength distributions at short lengths which allow for this bimodal distribution may give better agreem e n t b e t w e e n the c a l c u l a t e d strength of composite models based on fibre bundle strength at short lengths and the observed composite strength. (Authors' abstract) ESCA studies of carbon and oxygen in carbon fibres Hopfgarten, F. Fibre Science and Technology Vol 12 No 4 (July 1979) pp 283-294 Seven commercial carbon fibre qualities were s t u d i e d , two f r o m Torayca, two from Courtaulds and three from Union Carbide. These carbon fibres can be divided into three groups: Type 1, Torayca M40A and Courtaulds H M - S ; T y p e 2, Union Carbide Thornel 300 and two types of Union Carbide 'pitch' carbon fibre; and Type 3, Torayca T 2 0 0 A and Courtaulds A-S. The ESCA examination shows that the Type 1 carbon fibres have a structure more similar to the graphite structure than the other two types of carbon fibres. The examination also shows that one type of the pitch carbon fibres has a large amount of oxygen single bonded to carbon
COMPOSITES. JANUARY 1980
within the fibre. The studies also indicate for Types 2, 3 and 'pitch' carbon fibres that besides oxygen atoms, sulphur and/or chlorine atoms are bonded to carbon atoms within the fibres. (Author's abstract)
CEMENT MA TRICES
Fiexural creep behaviour of fibrereinforced cement composites Swamy, R.N. and Theodorakopoulos. D.D. The International Journal of Cement Composites Vol 1 No 1 (May 1979) pp 37-47 Tests are reported on the drying shrinkage and flexural creep of mortar and concrete specimens reinforced with steel, glass, and a mixture of glass and polypropylene fibres. It is shown that fibre reinforcement exercises a clear and distinct restraining influence on the shrinkage movements of the unreinforced matrix. The fibrereinforcement also reduced considerable the deflections under sustained flexural load. Both tensile and flexural creep properties were reduced substantially by the presence of fibres. Fibres were generally more effective in controlling compressive creep than tensile creep of the unreinforced matrix. (Authors' abstract)
High temperature polymer concretes from organosiloxane resins Z e l d i n , A . N . , F o n t a n a , J,J., Kukacka, L.E. and Carciello, N.R. The International Journal of Cement Composites Vol 1 No 1 (May 1979) pp 11-17 The feasibility of using the products of free-radical copolymerization of organosiloxanes in the formation of polymer concrete that is thermally and chemically stable in hydrotherreal environments has been demonstrated. The use of organosiloxanes containing pendant organic groups in polymer concrete results in a
composite with high compressive strength and thermal and hydrolytic stability. The effects of monomer and initiator concentrations and aggregate composition have been studied and the results are discussed. (Authors' abstract)
Polypropylene fibre reinforced cement Dave, N.J. and Ellis, D.G. The International Journal of Cement Composites Vol 1 No 1 (May 1979) pp 19-28 It is shown experimentally that thin cement sections reinforced with chopped polypropylene fibres can sustain useful stresses in three point bending beyond a first crack stress. Cement discs incorporating chopped filaments and fihn fibres are prepared by a mixing, dewatering and pressing technique. One preparation method is chosen, and in turn, each of the parameters, viz fibre area of cross-section, length, concentration, and Young's modulus, is increased with the other parameters remaining constant. The highest post crack flexural stresses are achieved for the highest fibre concentration and the finest, longest fibres which can be satisfactorily and homogeneously incorporated in the cement, and for the highest fibre Young's modulus. These reinforced samples with improved ductibility exhibit multiple cracking, resulting from the reinforcement of the brittle cement matrix by the polypropylene fibres of higher tensile strength and strain-to-failure than the matrix. (Authors' abstract)
Serviceability of ferrocement subjected to flexural fatigue Balagaru, P.N., Naaman, A.E. and Shah, S.P. The International Journal of Cement Composites Vol 1 No 1 (may 1979) pp 3-9 An attempt to evaluate the influence of fatigue loading on the behaviour
51
CA RBON FIBRES
The dependence of the strength of carbon fibres on length Hitchon, J.W. and Phillips, D.C. Fibre Science and Technology Vol 12 No 3 (May 1979) pp 217-233 The strength distributions of Type 1 and Type 2 carbon fibres were measured at lengths of 0.5, 5, and 50mm, and the usefulness of the Weibull treatment in correlating the results tested. Weibull treatment did not accurately extrapolate strength distribution data obtained at longer lengths (50 r a m ) d o w n to fibrematrix transfer lengths (ca. 0.5 mm ): it is suggested that this failure may be due to a bimodal distribution of flaw sizes in the carbon fibre. It is suggested that modified estimates of fibre strength distributions at short lengths which allow for this bimodal distribution may give better agreem e n t b e t w e e n the c a l c u l a t e d strength of composite models based on fibre bundle strength at short lengths and the observed composite strength. (Authors' abstract) ESCA studies of carbon and oxygen in carbon fibres Hopfgarten, F. Fibre Science and Technology Vol 12 No 4 (July 1979) pp 283-294 Seven commercial carbon fibre qualities were s t u d i e d , two f r o m Torayca, two from Courtaulds and three from Union Carbide. These carbon fibres can be divided into three groups: Type 1, Torayca M40A and Courtaulds H M - S ; T y p e 2, Union Carbide Thornel 300 and two types of Union Carbide 'pitch' carbon fibre; and Type 3, Torayca T 2 0 0 A and Courtaulds A-S. The ESCA examination shows that the Type 1 carbon fibres have a structure more similar to the graphite structure than the other two types of carbon fibres. The examination also shows that one type of the pitch carbon fibres has a large amount of oxygen single bonded to carbon
COMPOSITES. JANUARY 1980
within the fibre. The studies also indicate for Types 2, 3 and 'pitch' carbon fibres that besides oxygen atoms, sulphur and/or chlorine atoms are bonded to carbon atoms within the fibres. (Author's abstract)
CEMENT MA TRICES
Fiexural creep behaviour of fibrereinforced cement composites Swamy, R.N. and Theodorakopoulos. D.D. The International Journal of Cement Composites Vol 1 No 1 (May 1979) pp 37-47 Tests are reported on the drying shrinkage and flexural creep of mortar and concrete specimens reinforced with steel, glass, and a mixture of glass and polypropylene fibres. It is shown that fibre reinforcement exercises a clear and distinct restraining influence on the shrinkage movements of the unreinforced matrix. The fibrereinforcement also reduced considerable the deflections under sustained flexural load. Both tensile and flexural creep properties were reduced substantially by the presence of fibres. Fibres were generally more effective in controlling compressive creep than tensile creep of the unreinforced matrix. (Authors' abstract)
High temperature polymer concretes from organosiloxane resins Z e l d i n , A . N . , F o n t a n a , J,J., Kukacka, L.E. and Carciello, N.R. The International Journal of Cement Composites Vol 1 No 1 (May 1979) pp 11-17 The feasibility of using the products of free-radical copolymerization of organosiloxanes in the formation of polymer concrete that is thermally and chemically stable in hydrotherreal environments has been demonstrated. The use of organosiloxanes containing pendant organic groups in polymer concrete results in a
composite with high compressive strength and thermal and hydrolytic stability. The effects of monomer and initiator concentrations and aggregate composition have been studied and the results are discussed. (Authors' abstract)
Polypropylene fibre reinforced cement Dave, N.J. and Ellis, D.G. The International Journal of Cement Composites Vol 1 No 1 (May 1979) pp 19-28 It is shown experimentally that thin cement sections reinforced with chopped polypropylene fibres can sustain useful stresses in three point bending beyond a first crack stress. Cement discs incorporating chopped filaments and fihn fibres are prepared by a mixing, dewatering and pressing technique. One preparation method is chosen, and in turn, each of the parameters, viz fibre area of cross-section, length, concentration, and Young's modulus, is increased with the other parameters remaining constant. The highest post crack flexural stresses are achieved for the highest fibre concentration and the finest, longest fibres which can be satisfactorily and homogeneously incorporated in the cement, and for the highest fibre Young's modulus. These reinforced samples with improved ductibility exhibit multiple cracking, resulting from the reinforcement of the brittle cement matrix by the polypropylene fibres of higher tensile strength and strain-to-failure than the matrix. (Authors' abstract)
Serviceability of ferrocement subjected to flexural fatigue Balagaru, P.N., Naaman, A.E. and Shah, S.P. The International Journal of Cement Composites Vol 1 No 1 (may 1979) pp 3-9 An attempt to evaluate the influence of fatigue loading on the behaviour
51