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Gypsum filler in polyesters
Vol. 18, No. 8,
TECHNICAL GYPSUM FILLER IN POLYESTERS
Page 2
NOTES
Calcium sulphate dihydrate (gypsum) is suggested as a replacement for calcium carbonate/aluminium trihydrate combinations in fire retardant reinforced polyester compounds on grounds of costsavings. Such compounds are used to produce plastics baths and shower units, and alumina trihydrate is included in order to meet building codes on fire retardancy. Gypsum, with its water of hydration, imparts similar flame and smoke suppression whilst acting also as a filler/reinforcement. It does, however, result in higher compound viscosities and lower loadings are necessary than those for calcium carbonate/ATH. This article reports on the evaluation of gypsum/polyester formulations in respect of their curing, rheology, water resistance, flame and smoke generation, and laminate physical properties. Plast. Eng., 1988, XLIV, (Mar.), 59
INJECTION MOULDING CANNON PIBRE REINFORCED POLYCARBONATE
In order for fibre reinforcements in thermoplastics to be as effective as possible, the fibres must be firmly bonded to the matrix resin and fibre length should be as long as possible. Using carbon fibres that were specially treated to promote adhesion to polycarbonate, an investigation was conducted to determine the physical properties attainable when the fibre matrix mixture is processed directly in an injection moulding machine. It was found that higher values for tensile and flexural strength were attained in comparison with a commercially available, compounded material. Kunststoffe,
THERMALLY CONDUCTIVE PLASTICS
1988,
78,
(Apr.), 308-313
Plastics can be changed into partially conductive materials with the addition of certain modifiers. Glass, while usually added as a reinforcing agent, also increases thermal conductivity. The normal range of c2nductivity for unfilled resins is 0.1 to 0.2 Btu hour x (feet) x 'F/foot while for 29-30% glass filled versions it is 0.15 to 0.25 Btu/hour x (feet) x OF/foot. Talc Spherical metal powders filled materials may show no change. can increase heat transfer through a resin, but because of their low aspect ratios and high densities, high loadings, often over 50 weight percent, must be used. To dramatically change property profiles, conductive modifiers must with high aspect ratios (length to diameter or thickness) Included in this family be incorporated into the base resin. of particulates are quick quenched aluminium fibres and flakes. Flakes tend to orient parallel to the plane of flow during the Cont./......
ADDITIVES FOR POLYMERS
o 1982 Elvvier SciencePublishersLtd.. Enghd./8&%0.00 + 2.20 No part ofthis publication may be reproduced. stored in a retrieval system. or transmitted by any form or by an! means, electronic. mechanical. photocopying, recording or otherwise. without the prior permission of the publishers. (Readers in the U.S.A. - please see special regulations listed on back cover.)
TECHNICAL GYPSUM FILLER IN POLYESTERS
Page 2
NOTES
Calcium sulphate dihydrate (gypsum) is suggested as a replacement for calcium carbonate/aluminium trihydrate combinations in fire retardant reinforced polyester compounds on grounds of costsavings. Such compounds are used to produce plastics baths and shower units, and alumina trihydrate is included in order to meet building codes on fire retardancy. Gypsum, with its water of hydration, imparts similar flame and smoke suppression whilst acting also as a filler/reinforcement. It does, however, result in higher compound viscosities and lower loadings are necessary than those for calcium carbonate/ATH. This article reports on the evaluation of gypsum/polyester formulations in respect of their curing, rheology, water resistance, flame and smoke generation, and laminate physical properties. Plast. Eng., 1988, XLIV, (Mar.), 59
INJECTION MOULDING CANNON PIBRE REINFORCED POLYCARBONATE
In order for fibre reinforcements in thermoplastics to be as effective as possible, the fibres must be firmly bonded to the matrix resin and fibre length should be as long as possible. Using carbon fibres that were specially treated to promote adhesion to polycarbonate, an investigation was conducted to determine the physical properties attainable when the fibre matrix mixture is processed directly in an injection moulding machine. It was found that higher values for tensile and flexural strength were attained in comparison with a commercially available, compounded material. Kunststoffe,
THERMALLY CONDUCTIVE PLASTICS
1988,
78,
(Apr.), 308-313
Plastics can be changed into partially conductive materials with the addition of certain modifiers. Glass, while usually added as a reinforcing agent, also increases thermal conductivity. The normal range of c2nductivity for unfilled resins is 0.1 to 0.2 Btu hour x (feet) x 'F/foot while for 29-30% glass filled versions it is 0.15 to 0.25 Btu/hour x (feet) x OF/foot. Talc Spherical metal powders filled materials may show no change. can increase heat transfer through a resin, but because of their low aspect ratios and high densities, high loadings, often over 50 weight percent, must be used. To dramatically change property profiles, conductive modifiers must with high aspect ratios (length to diameter or thickness) Included in this family be incorporated into the base resin. of particulates are quick quenched aluminium fibres and flakes. Flakes tend to orient parallel to the plane of flow during the Cont./......
ADDITIVES FOR POLYMERS
o 1982 Elvvier SciencePublishersLtd.. Enghd./8&%0.00 + 2.20 No part ofthis publication may be reproduced. stored in a retrieval system. or transmitted by any form or by an! means, electronic. mechanical. photocopying, recording or otherwise. without the prior permission of the publishers. (Readers in the U.S.A. - please see special regulations listed on back cover.)