摘要:
The present invention is stereoregular poly{methyl(3,3,3-trifluoropropyl)siloxane} polymers and copolymers and methods for their making. The process involves reacting isomers of 1,3,5-trimethyl-1,3,5-tris(3',3',3'-trifluoropropyl)cyclotrisiloxane in the presence of an aprotic polar promoter and a lithium compound. The lithium compound initiates ring opening and polymerization of the isomers without effecting the steric arrangement of the isomers. Elastomers prepared by cross-linking polymers of the present invention can have sufficient cis 3,3,3-trifluoropropyl substitution to allow the elastomers to strain crystallize and provide reinforcement to the elastomers at typical use temperatures.
摘要:
Strain-crystallizing poly{methyl(3,3,3-trifluoropropyl)siloxane} elastomers and methods for their making. The process comprises the cross-linking of cis stereoregular polymers prepared by reacting isomers of 1,3,5-trimethyl-1,3,5-tris(3',3',3'-trifluoropropyl)cyclotrisiloxane, where at least 30 percent of the isomers are of cis configuration, in the presence of an aprotic polar promoter and a lithium compound. The lithium compound initiates ring opening and polymerization of the isomers without affecting the steric arrangement of the leomars. Elastomers prepared by cross-linking these cis stereoregular polymers have sufficient cis 3,3,3-trifluoropropyl substitution to allow the elastomers to strain crystallize and provide reinforcement to the elastomers at typical use temperatures.
摘要:
A stable aqueous dispersion and process for making the dispersion are provided containing hydrolyzed cellulose ester, organic solvent, water and acrylic resin having free acid functionalities that are at least partially neutralized. The dispersion is useful in coatings and can also contain surfactant and cross-linking agent.
摘要:
A stable aqueous dispersion and process for making the dispersion are provided containing hydrolyzed cellulose ester, organic solvent, water and acrylic resin having free acid functionalities that are at least partially neutralized. The dispersion is useful in coatings and can also contain surfactant and cross-linking agent.
摘要:
The specification discloses a process for the manufacture of cellulose acetate. The process reacts, at a temperature suitable for acetylation, an acetic acid activated pretreated cellulose raw material containing 100 parts cellulose by dry weight, and 0.5 to 40 parts of a bisulfate catalyst by dry weight of the cellulose. The bisulfate catalyst is selected from lithium bisulfate, sodium bisulfate, and potassium bisulfate. To enhance mixing with the activated and pretreated cellulose, the catalyst may be mixed with 2 to 4 parts of acetic anhydride by dry weight of the cellulose, and 4 to 6 parts of acetic acid by dry weight of the cellulose. In a further embodiment, 0.05 to 10 parts of a strong Bronsted acid by weight of the dry cellulose may be added as a co-catalyst.
摘要:
Novel coating compositions containing modified cellulose esters are disclosed. The modified cellulose esters contain acid functionality, permitting their dispersion in aqueous systems. The modified cellulose esters are particularly useful as rheology control agents in coatings which are applied as waterborne dispersions. The novel coating compositions are used to produce coated substrates with desirable appearance characteristics.
摘要:
Modified starch ester-urethanes prepared by reacting a starch ester containing residual hydroxyl groups with an ethylenically unsaturated isocyanate. The grafted starch ester is a urethane-containing product having pendent groups such as alphamethylstyrene and/or methacrylate moieties. The starch ester-urethane is capable of undergoing crosslinking reactions on exposure to ultraviolet radiation in the presence of a photoinitiator, and optionally ethylenically unsaturated monomers or oligomers. The ethylenically unsaturated starch ester-urethanes of this invention are useful for protective coatings for wood, metal, and plastics.