Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – From carboxylic acid or derivative thereof
Patent
1995-10-02
1998-12-08
Hampton-Hightower, P.
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
From carboxylic acid or derivative thereof
528345, 528422, 528423, 521 27, 4284111, 210500, 21050021, 210600, C08G 7306, B01D 7162
Patent
active
058470751
DESCRIPTION:
BRIEF SUMMARY
This invention relates to a novel type of polymer, and its use in structures having high porosity, for example porous membranes for use in, e.g. ultrafiltration, nanofiltration and reverse osmosis.
Accordingly the present invention provide's a polymer characterised by the presence of ylid linkages in the main polymer chain of the formula ##STR2## where the dashed line represents the remainder of a ring system for which the N.sup.+ provides a heteroatom, and E is a strongly electron withdrawing group.
The ring system is preferably monocyclic (e.g. having a total of 6 atoms) but may also, for example, be a fused ring system. Preferably the N.sup.+ provides the sole nitrogen atom in the ring species and preferably also there are no other ring heteroatoms.
The ring preferably has 6 ring atoms.
In a preferred embodiment, therefore, the invention provides a polymer characterised by presence of linkages in the polymer main chain of the formula (I) ##STR3## where E is a strongly electron withdrawing group.
Examples of the group E include carbonyl and sulphonyl.
Such polymers of the present invention are of use as membranes for ultrafiltration, nanofiltration and reverse osmosis, and display considerable hydrophilicity, absorbing up to 20% water on exposure to atmospheric moisture, and yet the membranes are robust and have sufficiently high strength to withstand pressures applied across the membrane structures in use for ultrafiltration, nanofiltration and reverse osmosis.
These polymers and porous membranes of these polymers are easily prepared.
The polymer of the present invention may be unbranched or branched-chain and may optionally be cross-linked.
An unbranched polymer of the present invention may be a polymer characterised by the presence of units in the polymer main chain of the formula (IIA): ##STR4## where A is an acyclic or cyclic organic diradical, or a combination of such diradicals.
An unbranched polymer of the present invention may be a linear, rigid-rod type of polymer of the formula (IIB) below: ##STR5## where A.sup.1 is a linear acyclic organic diradical, or cyclic organic para-diradical, or a combination of, such diradicals, and n is 3 to 3000.
An unbranched polymer of this type of rigid, unbranched molecular structure could, in principle, give rise to anisotropic (i.e. liquid-crystalline) solutions in which at least a proportion of the unbranched polymer molecules exist in ordered domains and are self-orienting under mild shear.
Sheets and fibres of such materials produced under shear will tend to be highly oriented and hence characterised by desirably high tensile moduli.
An unbranched polymer of the present invention may be of the formula (IIIA): ##STR6## wherein n is 3 to 3000;
E.sup.1 is independently carbonyl or sulphonyl; and heteroarenediyl, or a combination of such diradicals.
Examples of A.sup.2 unbranched alkanediyl include optionally substituted polymethylene.
Examples of A.sup.2 cycloalkanediyl include cyclohexane-1,4-diyl and cyclohexane-1,3-diyl.
Examples of A.sup.2 Arenediyl include 1,4-phenylene, 1,3-phenylene, 4,4'-biphenylene, 4,4'-oxybiphenylene naphthalene-2,6-diyl, and hexafluoroisopropylidene-4,4-bis(phenylene).
Examples of A.sup.2 heteroarenediyl include pyridine-2,5-diyl, pyridine-2,6-diyl, and pyridine-3,5-diyl.
Examples of A.sup.2 which is a combination of such diradicals include para-xylylene and meta-xylylene.
A linear rigid rod unbranched polymer of the present invention may be of the formula (IIIB): ##STR7## where A.sup.3 is unbranched alkanediyl, or para-cycloalkanedlyl, para-arenediyl or para-heteroarenediyl, each cyclic species having an even number of ring atoms, or a combination of such diradicals.
Examples of A.sup.3 unbranched alkanediyl include optionally substituted polymethylene.
Examples of A.sup.3 para-cycloalkanediyl, having an even number of ring atoms include cyclohexane-1,4-diyl.
Examples of A.sup.3 para-arenediyl having an even number of ring atoms include 1,4-phenylene, and 4,4'-biphenylene.
Examples of A.sup.3 para-heteroarenediyl having an even n
REFERENCES:
patent: 4119581 (1978-10-01), Rembraum et al.
patent: 4994209 (1991-02-01), Okazaki
Colquhoun Howard Matthew
Lewis Andrew Lennard
Hampton-Hightower P.
North West Water Group PLC
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