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Thermoxidative degradation of polypropylene
Vol. 18, No. 7, Page 3 1.6 g,'cm3. Although the additive does not become chemically bound into the cured polymer system, it passes heat-ageing and automotive leaching tests. Firemaster 836 is marketed by Great Lakes Chemical.
THEBMOXIDATIVE DEGRADATION OF POLYPROPYLENE
The thermoxidative behaviour of atactic and isotactic polypropylene under dynamical thermoxidative conditions has been studied at the Institute of Macromolecular Chemistry in Romania. It has been established that, with the increase of the heating rate, the development of the oxidative processes are diminished and consequently a modification in the reaction mechanism takes place. The oxidative processes are more intense in the case of the atactic polymer. The 5-15'C/min heating rates determine significant differences between the thermal behaviour of the samples, permitting the elaboration of the standard curves useful in fast determination of the atactic content of the industrial products by routine analysis.
J. Poly. Sci., Part A, 1988,26, 1639-1647
S~LI~,~~D ACCELERATED APING
Spectroradiometric measurements were made to quantify the wide variations in UV content of sunlight during summer and winter. Accelerated weathering tests are widely used for research and deve lThey employ opment, quality control and material certification. a variety of light sources to simulate sunlight and the damage Comparative spectroradiometric measurements caused by sunlight. of various types of accelerated testers also showed a wide variety of UV spectra. These measurements help highlight the advantages and disadvantages of the various accelerated light sources.
Kunststoffe, 1988,78, (Apr.), 323-327
A paper presented at the Plast 88 conference under the Composites sector dealt with fibre technology in relation to their use in composite materials. Organic fibres have developed from low modulus linear molecular thermoplastic fibres,such as nylon, through to very high modulus aramid fibres based on a rigid complicated para-crystalline molecular structure.
FIBRE TECHNOLOGY
The production methods have changed in order to achieve these results. Low modulus thermoplastic fibres are produced by a drawing process, usually from the melt, whereas liquid crystal technolGlass ogy is employed to produce high modulus organic fibres. fibres which were the first reinforcement produced for composites are still most widely used, however, and shortcomings of relatively high density and low elastic modulus have been overcome by the production of high modulus filaments such as carbon and boron fibres. Boron fibre is an example of a remarkable finding almost no market because of its
ADDITIVES
FOR
POLYMERS
technical achievement cost. Carbon fibres Cont./......
Q 1868 Elmvkr Science Publiobara Ltd.. Englutd.nuvrO.00 + 220 No part of this publication may be reproduced. stored in a retrieval system, or transmitted by any form or by any 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.)
THEBMOXIDATIVE DEGRADATION OF POLYPROPYLENE
The thermoxidative behaviour of atactic and isotactic polypropylene under dynamical thermoxidative conditions has been studied at the Institute of Macromolecular Chemistry in Romania. It has been established that, with the increase of the heating rate, the development of the oxidative processes are diminished and consequently a modification in the reaction mechanism takes place. The oxidative processes are more intense in the case of the atactic polymer. The 5-15'C/min heating rates determine significant differences between the thermal behaviour of the samples, permitting the elaboration of the standard curves useful in fast determination of the atactic content of the industrial products by routine analysis.
J. Poly. Sci., Part A, 1988,26, 1639-1647
S~LI~,~~D ACCELERATED APING
Spectroradiometric measurements were made to quantify the wide variations in UV content of sunlight during summer and winter. Accelerated weathering tests are widely used for research and deve lThey employ opment, quality control and material certification. a variety of light sources to simulate sunlight and the damage Comparative spectroradiometric measurements caused by sunlight. of various types of accelerated testers also showed a wide variety of UV spectra. These measurements help highlight the advantages and disadvantages of the various accelerated light sources.
Kunststoffe, 1988,78, (Apr.), 323-327
A paper presented at the Plast 88 conference under the Composites sector dealt with fibre technology in relation to their use in composite materials. Organic fibres have developed from low modulus linear molecular thermoplastic fibres,such as nylon, through to very high modulus aramid fibres based on a rigid complicated para-crystalline molecular structure.
FIBRE TECHNOLOGY
The production methods have changed in order to achieve these results. Low modulus thermoplastic fibres are produced by a drawing process, usually from the melt, whereas liquid crystal technolGlass ogy is employed to produce high modulus organic fibres. fibres which were the first reinforcement produced for composites are still most widely used, however, and shortcomings of relatively high density and low elastic modulus have been overcome by the production of high modulus filaments such as carbon and boron fibres. Boron fibre is an example of a remarkable finding almost no market because of its
ADDITIVES
FOR
POLYMERS
technical achievement cost. Carbon fibres Cont./......
Q 1868 Elmvkr Science Publiobara Ltd.. Englutd.nuvrO.00 + 220 No part of this publication may be reproduced. stored in a retrieval system, or transmitted by any form or by any 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.)