Direct bonding of natural rubber to nitrile rubber

Campion R. P., . Direct bonding of natural rubber to nitrile rubber. pp. 67-81. ISSN 0127-7065

Strong bonds can form between natural rubber (NR) and nitrite rubber compounds when held together during vulcanisation if the former is modified by the addition of liquid polybutene as a compatible extender. Successful bonding is also dependent on the vulcanisation systems employed. It is suggested that the phenomenon be regarded as one of liquid-solid contact. A NR compound thus modified is sufficiently fluid to wet under moulding pressure a high-viscosity nitrile rubber surface (nationally a solid) before vulcanisation is well-established. As the NR compound possesses the lower surface tension (or energy) the system is thermodynamically favourable. Regarding the vulcanisation systems a fast-curing nitrile compound is required to maintain the notional solid role. Bond strengths decrease progressively as the NR vulcanisation system is changed from conventional through semi-EV to EV; high strengths are apparently associated with the many polysulphidic crosslinks which form for conventional systems during early stages of vulcanisation. It may require the relatively long lengths of polysulphidic crosslinks to traverse the bond interface. An alternative suggestion is that bond formation arises from the maturation reactions of polysulphidic crosslinks near the interface. Bonds were not affected by immersion in either sea water or ASTM No. 3 oil for thirty days at room temperature. The polybutene levels used did not reduce the NRs high tearing energy characteristics and reduced hardness and modulus by only 10.

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Abstract

Strong bonds can form between natural rubber (NR) and nitrite rubber compounds when held together during vulcanisation if the former is modified by the addition of liquid polybutene as a compatible extender. Successful bonding is also dependent on the vulcanisation systems employed. It is suggested that the phenomenon be regarded as one of liquid-solid contact. A NR compound thus modified is sufficiently fluid to wet under moulding pressure a high-viscosity nitrile rubber surface (nationally a solid) before vulcanisation is well-established. As the NR compound possesses the lower surface tension (or energy) the system is thermodynamically favourable. Regarding the vulcanisation systems a fast-curing nitrile compound is required to maintain the notional solid role. Bond strengths decrease progressively as the NR vulcanisation system is changed from conventional through semi-EV to EV; high strengths are apparently associated with the many polysulphidic crosslinks which form for conventional systems during early stages of vulcanisation. It may require the relatively long lengths of polysulphidic crosslinks to traverse the bond interface. An alternative suggestion is that bond formation arises from the maturation reactions of polysulphidic crosslinks near the interface. Bonds were not affected by immersion in either sea water or ASTM No. 3 oil for thirty days at room temperature. The polybutene levels used did not reduce the NRs high tearing energy characteristics and reduced hardness and modulus by only 10.

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Item Type:	Article
AGROVOC Term:	Natural rubber
AGROVOC Term:	Nitrites
AGROVOC Term:	Vulcanization
AGROVOC Term:	Elastomers
AGROVOC Term:	Liquids
AGROVOC Term:	Temperature
AGROVOC Term:	Strength
AGROVOC Term:	Bonded work
AGROVOC Term:	Adhesiveness
Depositing User:	Ms. Suzila Mohamad Kasim
Last Modified:	24 Apr 2025 06:28
URI:	http://webagris.upm.edu.my/id/eprint/23573

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