GB2088396A

GB2088396A - Aromatic Ethersulphone Copolymers

Info

Publication number: GB2088396A
Application number: GB8133149A
Authority: GB
Original assignee: Imperial Chemical Industries Ltd
Current assignee: Imperial Chemical Industries Ltd
Priority date: 1980-11-27
Filing date: 1981-11-03
Publication date: 1982-06-09
Also published as: GB2088396B

Abstract

An aromatic ethersulphone copolymer comprising 80 to 10 mole 5, preferably 70 to 40 mole %, of repeat units of formula <IMAGE> and correspondingly 20 to 90 mole %, preferably 30 to 60 mole %, of repeat units of formula <IMAGE>

Description

SPECIFICATION Aromatic Ethersulphone Copolymers The present invention relates to certain aromatic ethersulphone copolymers.

Aromatic polyethersulphone homopolymers having the repeat unit of formula

which reduces to

are commercially available thermoplastics polymers. They exhibit excellent mechanical performance at elevated temperatures, possess high strength and toughness and excellent resistance to fire and chemicals.

It has nevertheless been found that articles melt fabricated from these polymers have a tendency to exhibit internal crazing when immersed in hot water.

We have now discovered copolymers containing the above-mentioned repeat units which have a significantly improved resistance to hot water crazing.

According to the present invention there is provided an aromatic ethersulphone copolymer comprising 80 to 10 mole %, preferably 70 to 40 mole %, of repeat units of formula

and correspondingly 20 to 90 mole %, preferably 30 to 60 mole %, of repeat units of formula

The aromatic ethersulphone copolymers of the invention possess significantly improved resistance to hot water crazing in comparison to homopolymers of repeat unit A.

The aromatic ethersulphone copolymers of the present invention may be prepared by condensing appropriate proportions of the alkali metal salts of 4,4'-dihydroxydiphenylsulphone and 4,4'-dihydroxy diphenyl with 4,4'-dihalo-diphenylsulphone, either in bulk, or in an appropriate solvent using the type of process described generally in British Patent 1 078 234. Alternatively, the aromatic ethersulphone copolymers may be prepared by reacting appropriate proportions of 4,4'-dihydroxydiphenylsulphone and 4,4'-dihydroxy-diphenyl with 4,4'-dihalo-diphenylsulphone in the presence of an alkali metal carbonate or bicarbonate using the type of process described generally in Canadian Patent 847 963. In both methods there should be substantially equimolar proportions of total bisphenol (or bisphenate) and dihalide.

Examples 1-3 A series of copolymers according to the invention (Examples 1-3) having 80--40 mole % of units A and correspondingly 20-60 mole % of units B were prepared by reacting appropriate proportions of 4,4'-dihydroxydiphenylsulphone and 4,4'-dihydroxy-diphenyl with 4,4'-dichlorodiphenylsulphone in the presence of K2CO3 and using diphenylsulphone as polymerisation solvent; the polymerisation temperatures were within the range 200--2900C. Substantially equimolar amounts of total bisphenol and dihalide were employed with a molar amount of K2CO3 being slightly in excess of twice that of the dihalide.

Example 4 A number of homopolymers of repeat unit A were prepared from 4,4'-dihydroxydiphenylsulphone and 4,4'-dichloro-diphenylsulphone using the same preparative process as in Examples 1-3.

The hot water craze resistances (HWCR's) of the polymers of Examples 1-3 were determined as follows. The purified polymers were compression moulded at 300-3200C into discs 3 cm in diameter by 3 mm thick. The discs were then immersed in de-ionised water in a pressure vessel and the vessel heated to 1 C. The discs were left immersed for 4 days. The degree of resulting crazing of the discs was determined by comparing the treated polymer with a set of 1 0 standard photographs of homopolymer discs which had been hot water crazed to different extents. Thus the polymers were graded from 1; no crazing, to 10; extreme crazing. All observations were made microscopically at xl 2 magnification by reflected light, with the standard photographs taken under the same conditions.

The results of the above experiments are shown in the following Table 1.

Table 1

Polymer Composition Reduced Ex No Molar Ratio A/B Viscosity* HWCR Grade 1 80/20 0.39 5 2 60/40 0.33 3 3 40/60 0.40 4 4 100/- 0.40-0.36 7-10 *measured at 250 C on a solution of the polymer in dimethyl formamide containing 1 g of the polymer in 100 cm3 of solution.

Claims

1. An aromatic ethersulphone copolymer comprising 80 to 10 mole % of repeat units of formula

and correspondingly 20 to 90 mole % of repeat units of formula

2. An aromatic ethersulphone copolymer according to claim 1 which comprises 70 to 40 mole % of repeat units A and 30 to 60 mole % of repeat units B.