Strengthening polymer

Edgecombe BD, Stein JA, Frechet JMJ, Xu Z, Kramer EJ. The role of polymer architecture in strengthening polymer— polymer interfaces a comparison of graft, block, and random copolymers containing hydrogen-bonding moieties. Macromolecules 1998 31 1292-1304. 

H. R. Brown, Strengthening Polymer-Polymer Interfaces, in Polymer Blends Volume 2 Performance, D. R. Paul and G. B. Bueknall, Eds., Wiley, New York, 2000, Chapter 23. 

Dai C-A, Jandt KD, Iyengar DR, Slack NL, Dai KH, Davidson WB, Kramer EJ, Hui C-Y (1997) Strengthening polymer interfaces with triblock copolymers. Macromolecules 30 549-560... 

Of significant interest is the use of nanodiamond powders for strengthening polymer materials. Nanopowders of oxides obtained from clay are used for these purposes at present. In commercial production of nanopowders by detonation the cost of nanodiamond powders and nanooxides obtained from clay becomes commensurate. That is, there are almost no obstacles of economic character for broad introduction of diamond nanopowders. 

In this case, the components are mixed, the pH adjusted to about 6.0 with sodium hydroxide, and the solution appHed to the textile via a pad-dry-cure treatment. The combination of urea and formaldehyde given off from the THPC further strengthens the polymer and causes a limited amount of cross-linking to the fabric. The Na2HP04 not only acts as a catalyst, but also as an additional buffer for the system. Other weak bases also have been found to be effective. The presence of urea in any flame-retardant finish tends to reduce the amount of formaldehyde released during finishing. 

Tire Cord. Melamine resins are also used to improve the adhesion of mbber to reinforcing cord in tires. Textile cord is normally coated with a latex dip solution composed of a vinylpyridine—styrene—butadiene latex mbber containing resorcinol—formaldehyde resin.. The dip coat is cured prior to use. The dip coat improves the adhesion of the textile cord to mbber. Further improvement in adhesion is provided by adding resorcinol and hexa(methoxymethyl) melamine [3089-11 -0] (HMMM) to the mbber compound which is in contact with the textile cord. The HMMM resin and resorcinol cross-link during mbber vulcanization and cure to form an interpenetrating polymer within the mbber matrix which strengthens or reinforces the mbber and increases adhesion to the textile cord. Brass-coated steel cord is also widely used in tires for reinforcement. Steel belts and bead wire are common apphcations. Again, HMMM resins and resorcinol [108-46-3] are used in the mbber compound which is in contact with the steel cord to reinforce the mbber and increase the adhesion of the mbber to the steel cord. This use of melamine resins is described in the patent Hterature (49). 

Concrete Additives. Poly(vinyl acetate) was first used in concrete in the 1940s as a thermoplastic polymer to strengthen the concrete matrix. 

A variety of materials has been proposed to modify the properties of asphaltic binders to enhance the properties of the mix (112), including fillers and fibers to reinforce the asphalt—aggregate mixture (114), sulfur to strengthen or harden the binder (115,116), polymers (98,117—121), mbber (122), epoxy—resin composites (123), antistripping agents (124), metal complexes (125,126), and lime (127,128). AH of these additives serve to improve the properties of the binder and, ultimately, the properties of the asphalt—aggregate mix. 

More extensive roughening of an interface between incompatible polymers can be obtained by use of various types of copolymer, introduced at the interface as putative compatibilisers. The interface may be strengthened, as a result of interdiffusion and roughening on a nanoscale. Many elegant experiments have been done in this area. 

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