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High modulus reinforced plastics through wire reinforcement
Thermal expansion of boron-fiber/ aluminium composites Kreider, K. G. and Patarini, V. M. Metallurgical Transactions, Vol 1, No 12, pp 3431 3435 (December 1970) Composites were prepared by hot pressing of SiC-coated B fibres in a matrix of A1. The thermal expansion of the composites was measured between 25 C and 300 C, as a function of the volume fraction and of fibre orientation. The thermal expansion in the direction of the fibre axes was lower than that predicted by theoretical models and this was attributed to yielding in the matrix. The thermal expansion perpendicular to the fibres was in good agreement with the prediction of Schapery. (71/3/25) o
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requirements of chopped glass strand it is suggested that these have been met by N. V. Silenka 882. (71/4/18)
Development and test of CFRP helicopter tail rotor blades Bongers, B., Brunsch, K. and Jonda W. Reinforced Plastics, Vol 14, No 16, p 466 (December 1970) The design, development and manufacturing procedure of CFRP helicopter tail rotor blades, including the analysis of flapwise, chordwise, longitudinal and torsional stresses encountered in service, are discussed and the processing and production technique described in some detail. An investigation into the effects of lightning on CFRP structures is being carried out. (71/4/19)
RESIN MA TRICES
Advanced composite structure out performs metal Plastics Design and Processing, Vol i0, No 11, pp 22 23 (November 1970) A graphite-fibre/resin-matrix composite model fuselage section, 4ft long and 2ft in diameter, has been built and tested. Stiffness under axial loads and bending loads was twice as high as for an equivalent aluminium structure. The stiffness-to-density ratio was three times as high. Torsional modulus, failure load in bending and in shear, were all better than design requirements by about 10%. The weight saving of the graphite-plastics structure compared with aluminium was 27%. (71/4/15)
Applications of plastics Metallurgia, Vol 83, No 495, pp 19 20 (January 1971) A brief survey is given of recent developments in the use of plasticscomposites and non-composites in the construction of boats and cars and in the building industry. (71/4/16) Asbestos-reinforced thermoplastics Noga, E. A. and Woodams, R. T. SPE Journal, Vol 26, No 9, pp 23 - 28 (September 1970) Methods of predicting strength and modulus for a short-fibre composite are presented and these are applied to composites of chrysotile asbestos in a variety of thermoplastic matrices. An efficiency of reinforcement is calculated for asbestos fibres and this increases with increasing matrix modulus. (71/4/17)
The Downland resin injection unit (for pumping polyester resin into matched moulds) Reinforced Plastics, Vol 15, No 2/3 (March 19 71) The availability of continuous-filament glass mat has made economical, for certain applications, the technique of pumping polyester resin into the cavity between matched moulds. Chopped strand mat, on the other hand, will not resist the washing effect of the resin injected under pressure. High pressures are not required and since the volume of reinforcement is known accurately the quantity of resin may be finely controlled. The moulding cycle is, however, rather lengthy compared with the hot press moulding technique. (71/4/20)
Fast-curing polybut adiene setting resins
thermo-
Barth, H. J. and Robertson, J. J. Modern Plastics, Vol 47, No 11, pp 142 - 148 (November 1970) A new family of polybutadiene thermosetting resins possessing thermoplastic-like processing qualities coupled with extremely fast cure characteristics has been developed. These materials possess many admirable dielectric and mechanical properties, have a low rate of water absorption and a long shelf-life. This last asset, together with excellent blow processing characteristics, makes them ideal for preimpregnating laminates for composite manufacture. (71/4/21 )
Compounding and feeding systems for reinforced thermoplastics Nijssen, Th. Reinforced Plastics, Vol 14, No 15, p 437 (November 1970)
High modulus reinforced plastics through wire reinforcement Jaray, F. F. Plastics Rubbers and Textiles, Vol 1, No 12, p 481 (December 1970}
The methods of supply of reinforced thermoplastic granules to an injection moulding machine are briefly described and after a consideration of the
Steel wire reinforced sheet is finding increased applications. It compares with mild steel in mechanical properties and since it has very low built-in
stresses it can be used at permanent strains of up to 0"25% compared to the 0"1% maximum recommended by various standards authorities for GRP. (71/4/22)
How good is carbon fibre stiffened GRP? Plastics Rubbers and Textiles, Vol 1, No 12, pp 497 ~ 498 (December 1970) The effects of small additions of carbon fibre to GRP as unidirectional reinforcement are discussed. The properties are better than could be achieved by use of a c FR P framework. As little as 3% of carbon fibre doubles the stiffness of G RP. It also introduces a pseudo-metallic yielding behaviour at about half the UTS, which remains the same as for GRP alone. The cost of raw materials is trebled by the 3% addition at present prices but would be negligibly increased if the cost of carbon fibre fell to £13/kg. (71/4/23)
How to get more from glass fiberreinforced HDPE Bernado, A. C. SPE Journal, Vol 26, No 10, pp 39 45 fOctober 1970) Reinforcement type, strand length, surface treatment, polyethylene properties and processing route and their effect on composite properties are examined. Some important conclusions are: surface treatment of the glass is very important; strand length is not important since this is reduced to a characteristic value during processing; low-shear processing methods reduce glass length degradation and thus increase the characteristic value; a narrow molecular weight distribution in the polyethylene gives stronger composites. (71/4/24)
Liquid rubber for toughening thermoset resins Drake, R. S., Rowe, E. H., Siebert, A. R. and Riew, C. K. Reinforced Plastics, Vol 15, No 2/3, p 38 (March 1971) Hycar CTBN, a carboxyl terminated liquid butadiene acrylonitrile copolymet has been found effective in the toughening of epoxy resin systems and several CT BN specimens were prepared and examined in order to show the importance of molecular weight and acrylonitrile content on the optimization of the toughening effect. The acrylonitrile content of the CTBN appears more important for this purpose than either its molecular weight or the average particle size of the precipitated rubber particles. This article is presented better in the Proceedings of the 7th International Reinforced Plastics Conference organized by the British Plastics Federation, Brighton, October 1970. (71/4/25)
COMPOSITES June 1971 127
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requirements of chopped glass strand it is suggested that these have been met by N. V. Silenka 882. (71/4/18)
Development and test of CFRP helicopter tail rotor blades Bongers, B., Brunsch, K. and Jonda W. Reinforced Plastics, Vol 14, No 16, p 466 (December 1970) The design, development and manufacturing procedure of CFRP helicopter tail rotor blades, including the analysis of flapwise, chordwise, longitudinal and torsional stresses encountered in service, are discussed and the processing and production technique described in some detail. An investigation into the effects of lightning on CFRP structures is being carried out. (71/4/19)
RESIN MA TRICES
Advanced composite structure out performs metal Plastics Design and Processing, Vol i0, No 11, pp 22 23 (November 1970) A graphite-fibre/resin-matrix composite model fuselage section, 4ft long and 2ft in diameter, has been built and tested. Stiffness under axial loads and bending loads was twice as high as for an equivalent aluminium structure. The stiffness-to-density ratio was three times as high. Torsional modulus, failure load in bending and in shear, were all better than design requirements by about 10%. The weight saving of the graphite-plastics structure compared with aluminium was 27%. (71/4/15)
Applications of plastics Metallurgia, Vol 83, No 495, pp 19 20 (January 1971) A brief survey is given of recent developments in the use of plasticscomposites and non-composites in the construction of boats and cars and in the building industry. (71/4/16) Asbestos-reinforced thermoplastics Noga, E. A. and Woodams, R. T. SPE Journal, Vol 26, No 9, pp 23 - 28 (September 1970) Methods of predicting strength and modulus for a short-fibre composite are presented and these are applied to composites of chrysotile asbestos in a variety of thermoplastic matrices. An efficiency of reinforcement is calculated for asbestos fibres and this increases with increasing matrix modulus. (71/4/17)
The Downland resin injection unit (for pumping polyester resin into matched moulds) Reinforced Plastics, Vol 15, No 2/3 (March 19 71) The availability of continuous-filament glass mat has made economical, for certain applications, the technique of pumping polyester resin into the cavity between matched moulds. Chopped strand mat, on the other hand, will not resist the washing effect of the resin injected under pressure. High pressures are not required and since the volume of reinforcement is known accurately the quantity of resin may be finely controlled. The moulding cycle is, however, rather lengthy compared with the hot press moulding technique. (71/4/20)
Fast-curing polybut adiene setting resins
thermo-
Barth, H. J. and Robertson, J. J. Modern Plastics, Vol 47, No 11, pp 142 - 148 (November 1970) A new family of polybutadiene thermosetting resins possessing thermoplastic-like processing qualities coupled with extremely fast cure characteristics has been developed. These materials possess many admirable dielectric and mechanical properties, have a low rate of water absorption and a long shelf-life. This last asset, together with excellent blow processing characteristics, makes them ideal for preimpregnating laminates for composite manufacture. (71/4/21 )
Compounding and feeding systems for reinforced thermoplastics Nijssen, Th. Reinforced Plastics, Vol 14, No 15, p 437 (November 1970)
High modulus reinforced plastics through wire reinforcement Jaray, F. F. Plastics Rubbers and Textiles, Vol 1, No 12, p 481 (December 1970}
The methods of supply of reinforced thermoplastic granules to an injection moulding machine are briefly described and after a consideration of the
Steel wire reinforced sheet is finding increased applications. It compares with mild steel in mechanical properties and since it has very low built-in
stresses it can be used at permanent strains of up to 0"25% compared to the 0"1% maximum recommended by various standards authorities for GRP. (71/4/22)
How good is carbon fibre stiffened GRP? Plastics Rubbers and Textiles, Vol 1, No 12, pp 497 ~ 498 (December 1970) The effects of small additions of carbon fibre to GRP as unidirectional reinforcement are discussed. The properties are better than could be achieved by use of a c FR P framework. As little as 3% of carbon fibre doubles the stiffness of G RP. It also introduces a pseudo-metallic yielding behaviour at about half the UTS, which remains the same as for GRP alone. The cost of raw materials is trebled by the 3% addition at present prices but would be negligibly increased if the cost of carbon fibre fell to £13/kg. (71/4/23)
How to get more from glass fiberreinforced HDPE Bernado, A. C. SPE Journal, Vol 26, No 10, pp 39 45 fOctober 1970) Reinforcement type, strand length, surface treatment, polyethylene properties and processing route and their effect on composite properties are examined. Some important conclusions are: surface treatment of the glass is very important; strand length is not important since this is reduced to a characteristic value during processing; low-shear processing methods reduce glass length degradation and thus increase the characteristic value; a narrow molecular weight distribution in the polyethylene gives stronger composites. (71/4/24)
Liquid rubber for toughening thermoset resins Drake, R. S., Rowe, E. H., Siebert, A. R. and Riew, C. K. Reinforced Plastics, Vol 15, No 2/3, p 38 (March 1971) Hycar CTBN, a carboxyl terminated liquid butadiene acrylonitrile copolymet has been found effective in the toughening of epoxy resin systems and several CT BN specimens were prepared and examined in order to show the importance of molecular weight and acrylonitrile content on the optimization of the toughening effect. The acrylonitrile content of the CTBN appears more important for this purpose than either its molecular weight or the average particle size of the precipitated rubber particles. This article is presented better in the Proceedings of the 7th International Reinforced Plastics Conference organized by the British Plastics Federation, Brighton, October 1970. (71/4/25)
COMPOSITES June 1971 127