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Compression testing of fibre-reinforced plastics composites
Additives for Polymers
May 1993
applications in 50 of the most popular colours and grades. The company maintains close relationships with OEM colour stylists and has developed master lots of precoloured Lustran to help customers gain faster OEM colour approval for their compounds. Contact: The Chemical Group, Monsanto Co, 800 N. Lindbergh Blvd, St. Louis, MO 63167, USA. Tel: -11-314-694-8664.
Air Products polyurethane
markets Lonza curing agent
Air Products and Chemicals Inc has signed a long term agreement with Lonza Ltd and Lonza Inc. to market the Lonza high performance diamine curative, Lonzacure MCDEA [4,4’-methylene-bis (3-chloro-2,6diethyl aniline)]. Lonzacure MCDEA is used as a curative for TDI-based polyurethane prepolymers, and has been shown to produce a polyurethane elastomer with superior mechanical properties as compared to other The performance curatives. diamine improvements include an increased hardness, greater softening temperature, higher resilience, improved hydrolytic stability, and better dynamic properties. First introduced as a developmental product in 1989, Lonzacure MCDEA curative is now available in for the castable commercial quantities elastomer industry. Contact: Air Products and Chemicals, Hersham Place, Molesey Road, Walton-onnames, Surrey, KT19 4RZ, UK. Tel: +44932-249273. Telex: 917243.
TECHNICAL
BRIEFS
Compression testing of fibrereinforced plastics composites Compression testing of thin and slender specimens must take into consideration the inherent instability of such specimens. Four different procedures which address this problem of instability (tendency to buckle) were used to characterize a fibre-reinforced
Ol993 Elsevier Science Publishers Ltd
plastic (FRP) at the Loughborough University of Technology in the UK. It is demonstrated that the procedure adopted influences the Use of the Celanese results obtained. antibuckling guide recommended in ASTM standards gave rise to high values of compressive strength whereas complete edge support of specimens gave rise to high secant modulus values. Other guides gave results with much lower coefficients of variation. Possible explanations for these findings are presented and recommendations for use are made. (23 refs). Polymer Testing, 1993, 12, (I), 15-29
Density measurement of rice husk ash filler particles in polypropylene composites A simple method of determining filler material density is described. Rice husk ash which consists predominantly of silica serves as a filler in polypropylene. The filler density was determined from first principles using a pyknometer. The filler was compounded in polypropylene and the densities of the composites were measured using an electronic densimeter. The measured composite densities agree very closely with theoretical values calculated based on the measured density of the filler material. (4 refs). Polymer Testing, 1992, 12, (2), IO7-112
Effect of stabilizers on integrated chemiluminescence in relation to photo-oxidation of polypropylene The total chemiluminescence from polypropylene films heated in an inert atmosphere is a sensitive measurement of the hydroperoxide content in the induction period of photo-oxidation. The PP films show a very rapid increase in the hydroperoxide content in the early stages of photo-oxidation which could not be detected by ATR-IR or XPS analysis. This ‘appears as a .peak in all of the films which increases in area with film thickness, indicating it is a bulk property. These are believed to form by the rapid 9
May 1993
applications in 50 of the most popular colours and grades. The company maintains close relationships with OEM colour stylists and has developed master lots of precoloured Lustran to help customers gain faster OEM colour approval for their compounds. Contact: The Chemical Group, Monsanto Co, 800 N. Lindbergh Blvd, St. Louis, MO 63167, USA. Tel: -11-314-694-8664.
Air Products polyurethane
markets Lonza curing agent
Air Products and Chemicals Inc has signed a long term agreement with Lonza Ltd and Lonza Inc. to market the Lonza high performance diamine curative, Lonzacure MCDEA [4,4’-methylene-bis (3-chloro-2,6diethyl aniline)]. Lonzacure MCDEA is used as a curative for TDI-based polyurethane prepolymers, and has been shown to produce a polyurethane elastomer with superior mechanical properties as compared to other The performance curatives. diamine improvements include an increased hardness, greater softening temperature, higher resilience, improved hydrolytic stability, and better dynamic properties. First introduced as a developmental product in 1989, Lonzacure MCDEA curative is now available in for the castable commercial quantities elastomer industry. Contact: Air Products and Chemicals, Hersham Place, Molesey Road, Walton-onnames, Surrey, KT19 4RZ, UK. Tel: +44932-249273. Telex: 917243.
TECHNICAL
BRIEFS
Compression testing of fibrereinforced plastics composites Compression testing of thin and slender specimens must take into consideration the inherent instability of such specimens. Four different procedures which address this problem of instability (tendency to buckle) were used to characterize a fibre-reinforced
Ol993 Elsevier Science Publishers Ltd
plastic (FRP) at the Loughborough University of Technology in the UK. It is demonstrated that the procedure adopted influences the Use of the Celanese results obtained. antibuckling guide recommended in ASTM standards gave rise to high values of compressive strength whereas complete edge support of specimens gave rise to high secant modulus values. Other guides gave results with much lower coefficients of variation. Possible explanations for these findings are presented and recommendations for use are made. (23 refs). Polymer Testing, 1993, 12, (I), 15-29
Density measurement of rice husk ash filler particles in polypropylene composites A simple method of determining filler material density is described. Rice husk ash which consists predominantly of silica serves as a filler in polypropylene. The filler density was determined from first principles using a pyknometer. The filler was compounded in polypropylene and the densities of the composites were measured using an electronic densimeter. The measured composite densities agree very closely with theoretical values calculated based on the measured density of the filler material. (4 refs). Polymer Testing, 1992, 12, (2), IO7-112
Effect of stabilizers on integrated chemiluminescence in relation to photo-oxidation of polypropylene The total chemiluminescence from polypropylene films heated in an inert atmosphere is a sensitive measurement of the hydroperoxide content in the induction period of photo-oxidation. The PP films show a very rapid increase in the hydroperoxide content in the early stages of photo-oxidation which could not be detected by ATR-IR or XPS analysis. This ‘appears as a .peak in all of the films which increases in area with film thickness, indicating it is a bulk property. These are believed to form by the rapid 9