| 摘要 |
The invention comprises thiocyclobutanones of formula <FORM:1074600/C2/1> where R1 is C1- 12 alkyl, mononuclear carbocyclic aryl of up to 12 C, R2COO(CmH2m)-(where R2/h is H(CnH2n)- or R3R4CH-) or <FORM:1074600/C2/2> R3 and R4 are each H, C1- 8 alkyl, mononuclear carbocyclic aryl of up to 12 C, or together with the carbon atom to which they are attached complete a C5- 7 saturated carbocyclic ring; R5 is H or C1- 4 alkyl; and m and n are each 1 t 4. They are prepared by reacting a ketene R3R4C = CO with a vinyl thioether of formula R6-S-CH = CH-R5, where R6 is a radical which R1 may be, R5-CH = CH- or HO -(CmH2m)-.ALSO:Polymers such as polypropylene and, particularly, poly (methylmethacrylate) are thermally stabilized by means of thiocyclobutanes of formula <FORM:1074600/C3/1> where R1 is C1- 12 alkyl, mononuclear carbocyclic aryl of up to 12 C, R2COO(CmH2m)-(where R2/h is H(CnH2n)- or R3R4CH-) or <FORM:1074600/C3/2> R3 and R4 are each H, C1- 8 alkyl, mononuclear carbocyclic aryl of up to 12 C, or together with the carbon atom to which they are attached complete a C5- 7 saturated carbocyclic ring; R5 is H or C1- 4 alkyl; and m and n are each 1 to 4. The stablizers may be incorporated by milling on hot rolls, or may be added to the reactants before polymerization. In an example, a granular polymer suitable for moulding is obtained by polymerizing methyl methacrylate in an aqueous medium containing disodium acid phosphate, sodium hypophosphite, polysodium methacrylate, azobisisobutyronitrile and a thiocyclobutane compound. |
