Multiphase block and graft copolymers comprising a hydrophilic continuous phase and hydrophobic domains

• US 4,104,824 A
• Filed: 01/11/1977
• Issued: 08/08/1978
• Est. Priority Date: 02/27/1975
• Status: Expired due to Term

• Current Assignee: Exxon Research and Engineering Company (Exxon Mobil Corporation)
• Original Assignee: Exxon Research and Engineering Company (Exxon Mobil Corporation)
• Inventors: Lundberg, Robert D., Thame, Neville G.
• Primary Examiner(s): Bagwill, Robert E.
• Application Number:
  US05/758,421
• Time in Patent Office: 574 Days
• Field of Search: 47/9, 47/58, 47/DIG. 7, 47/DIG. 10, 47/DIG. 11, 260/857 G
• US Class Current: 47/58.10R
• CPC Class Codes: C08G 18/4833 Polyethers containing oxyethylene units
• CPC Class Codes: C08G 18/6204 Polymers of olefins unsaturated polymers of conjugated dienes C08G18/69
• CPC Class Codes: C08G 2210/00 Compositions for preparing hydrogels
• CPC Class Codes: C08G 2250/00 Compositions for preparing crystalline polymers
• CPC Class Codes: C08G 2310/00 Agricultural use or equipment
• CPC Class Codes: C08G 81/021 Block or graft polymers containing only sequences of polymers of C08C or C08F
• CPC Class Codes: Y10S 47/10 Physical and chemical treatment of agricultural soils

Abstract

This invention relates to thermoplastic, multiphase copolymers selected from the group consisting of copolymers represented by graft copolymers having the general formula ##STR1## AND BLOCK COPOLYMERS HAVING THE GENERAL FORMULA XB--[AB]_n --yA wherein n is an integer ≧ 1, m is > 1, x and y are 0 or 1, and y is 1 when n is 1, A is a thermoplastic, hydrophobic polymer block having a softening point (i.e., a glass transition or cyrstalline melting point) of at least 35° C and a molecular weight of at least 2,000, and B is a thermoplastic, hydrophilic polymer block having a softening point of at least about 35° C and a molecular weight of at least about 6,000, which comprises from about 30-97 wt % of said copolymer. The novel polymers of this invention are useful for making water containing gels. Preferably, the thermoplastic multiphase copolymer is a styrene-ethylene oxide copolymer. The novel polymers are made by a process which allows one to prepare a copolymer which is substantially free of homopolymeric impurities. The compositions of the instant invention are melt processable by conventional thermoplastic techniques.

Claims

1. A method of promoting the survival and growth of plants which comprises admixing with the plant growth medium in which said plants are grown from about 25 weight percent of a thermoplastic copolymer having an average molecular weight of at least 10,000, selected from the group consisting of copolymers represented by graph copolymers having the general formula ##STR9## and block copolymers having the general formula xB--[AB]_n --yA wherein n is an integer ≧

1, m is >

1, x and y are 0 or 1, and y is 1 when n is 1, A is a thermoplastic hydrophobic polymer block having a softening point of at least 35°

C and a molecular weight of at least 2,000, and B is a thermoplastic hydrophilic polymer block having a softening point of at least about 35°

C and a molecular weight of at least about 6,000 and which comprises from about 30-97 weight % of said copolymer.

2. The method of claim 1 wherein B is selected from the group consisting of poly(ethylene oxide, polyacrylamide, poly-α

-hydroxyethylmethacrylate and copolymers thereof and comprises greater than 50% by weight of said composition, and A is selected from the group consisting of polystyrene, poly(t-butyl-styrene), polyvinyl, toluene, polymethylmethacrylate, polyacrylonitrile, polymethacrylonitrile, polylactones, polyamides and copolymers thereof.

3. The method of claim 2 wherein A is polystyrene.

4. The method of claim 1 wherein said thermoplastic copolymer is selected from the group consisting of block copolymers having the general formula xB--[AB]_n --yA wherein n is an integer ≧

1, x and y are 0 or 1, and y is 1 when n is 1, A is a thermoplastic hydrophobic polymer block having a softening point of at least 35°

C and a molecular weight of at least 2,000, and B is a thermoplastic hydrophilic polymer block having a softening point of at least about 35°

C and a molecular weight of at least about 6,000 and which comprises from about 30-97 weight % of said copolymer, said composition being further characterized as being substantially free from homopolymeric impurities.

5. The method of claim 4 wherein A is polystyrene and B is poly(ethylene oxide).

6. An improved method of planting agricultural seeds in a plant growth medium in which said seeds will germinate, said seeds being disposed within a polymeric tape, said tape being placed within said plant growth medium, wherein the improvement comprises forming said tape from a thermoplastic copolymer having an average molecular weight of at least 10,000, selected from the group consisting of copolymers represented by graph copolymers having the general formula ##STR10## and block copolymers having the general formula xB--[AB]_n --yA wherein n is an integer ≧

1, m is >

1, x and y are 0 or 1, and y is 1 when n is 1, A is a thermoplastic hydrophobic polymer block having a softening point of at least 35°

C and a molecular weight of at least 2,000, and B is a thermoplastic hydrophilic polymer block having a softening point of at least about 35°

C and a molecular weight of at least about 6,000 and which comprises from about 30-97 weight % of said copolymer, whereby said polymer absorbs and retains water thereby forming a water swollen tape disposed in said plant growth medium for improving said germination of said seeds.

7. The method of claim 6 wherein the water swollen composition comprises from about 30 to about 98 weight % water.

8. The method of claim 7 wherein said thermoplastic copolymer is selected from the group consisting of block copolymers having the general formula xB--[AB]_n --yA wherein n is an integer ≧

1, x and y are 0 or 1, and y is 1 when n is 1, A is a thermoplastic hydrophobic polymer block having a softening point of at least 35°

C and a molecular weight of at least 2,000, and B is a thermoplastic hydrophilic polymer block having a softening point of at least about 35°

C and a molecular weight of at least about 6,000 and which comprises from about 30-97 weight % of said copolymer, said composition being further characterized as being substantially free from homopolymeric impurities.

9. The method of claim 8 wherein A is polystyrene and B is poly(ethylene oxide).