The present invention relates to a method for polymerising an aqueous suspension of styrene using at least one organic hemiperoxyacetal peroxide, the method comprising a step a) of keeping the aqueous suspension of styrene comprising the organic hemiperoxyacetal peroxide at a temperature below the 1-hour half-life temperature of the organic hemiperoxyacetal peroxide, preferably at 5 to 25° C. below the 1-hour half-life temperature of the organic peroxide, for at least 30 minutes.

The present invention relates to a method for polymerising an aqueous suspension of styrene using at least one organic hemiperoxyacetal peroxide, the method comprising a step a) of keeping the aqueous suspension of styrene comprising the organic hemiperoxyacetal peroxide at a temperature below the 1-hour half-life temperature of the organic hemiperoxyacetal peroxide, preferably at 5 to 25° C. below the 1-hour half-life temperature of the organic peroxide, for at least 30 minutes.

A process for the production of a geopolymer composite. The disclosure further relates to a geopolymer composite, and the use of a geopolymer, a geopolymer in combination with an athermanous additive, or the geopolymer composite in expanded vinyl polymer, preferably vinyl aromatic polymer. Furthermore, the disclosure relates to a process for the production of expandable vinyl aromatic polymer granulate, and expandable vinyl aromatic polymer granulate. Finally, the disclosure relates to expanded vinyl foam, preferably vinyl aromatic polymer, and to a masterbatch comprising vinyl polymer and a), b), or c).

A process for the production of a geopolymer composite. The disclosure further relates to a geopolymer composite, and the use of a geopolymer, a geopolymer in combination with an athermanous additive, or the geopolymer composite in expanded vinyl polymer, preferably vinyl aromatic polymer. Furthermore, the disclosure relates to a process for the production of expandable vinyl aromatic polymer granulate, and expandable vinyl aromatic polymer granulate. Finally, the disclosure relates to expanded vinyl foam, preferably vinyl aromatic polymer, and to a masterbatch comprising vinyl polymer and a), b), or c).

Expandable methyl methacrylate resin particles capable of providing a foamed molded product which has excellent surface quality and with which a residue hardly remains after burning are provided. The expandable methyl methacrylate resin particles contain a base resin and a blowing agent. The base resin includes, as constitutional units, a specific amount of a methyl methacrylate unit, a specific amount of an acrylic ester unit, and a specific amount of a constitutional unit derived from a crosslinking agent. The expandable methyl methacrylate resin particles have a volume-average particle size of 0.30 mm to 0.50 mm.

Expandable methyl methacrylate resin particles capable of providing a foamed molded product which has excellent surface quality and with which a residue hardly remains after burning are provided. The expandable methyl methacrylate resin particles contain a base resin and a blowing agent. The base resin includes, as constitutional units, a specific amount of a methyl methacrylate unit, a specific amount of an acrylic ester unit, and a specific amount of a constitutional unit derived from a crosslinking agent. The expandable methyl methacrylate resin particles have a volume-average particle size of 0.30 mm to 0.50 mm.

A polyurethane foam article comprises the reaction product of an isocyanate component and isocyanate-reactive composition in the presence of a blowing agent. The isocyanate component includes an isocyanate prepolymer comprising the reaction product of a first polyether polyol and a methylene diphenyl diisocyanate. The isocyanate-reactive composition comprises a second polyether polyol having secondary terminal hydroxyl groups and an amine-initiated catalytic polyether polyol having primary hydroxyl groups. A method of making the polyurethane foam article comprises the steps of reacting the first polyether polyol and methylene diphenyl diisocyanate to form the isocyanate prepolymer and reacting the isocyanate prepolymer with the isocyanate-reactive composition in the presence of the blowing agent to form the polyurethane foam article.

A polyurethane foam article comprises the reaction product of an isocyanate component and isocyanate-reactive composition in the presence of a blowing agent. The isocyanate component includes an isocyanate prepolymer comprising the reaction product of a first polyether polyol and a methylene diphenyl diisocyanate. The isocyanate-reactive composition comprises a second polyether polyol having secondary terminal hydroxyl groups and an amine-initiated catalytic polyether polyol having primary hydroxyl groups. A method of making the polyurethane foam article comprises the steps of reacting the first polyether polyol and methylene diphenyl diisocyanate to form the isocyanate prepolymer and reacting the isocyanate prepolymer with the isocyanate-reactive composition in the presence of the blowing agent to form the polyurethane foam article.

Disclosed are a heat-expandable polyvinylidene chloride microsphere and its preparation method. The preparation method comprises: by weight, dissolving 250 to 550 parts of an aqueous-phase polymerization inhibitor, 20 to 100 parts of a dispersant, and 3 to 15 parts of a co-dispersing monomer in deionized water, adjusting a pH value of the solution and cooling the solution to obtain an aqueous phase for later use; dissolving 5 to 15 parts of a cross-linking agent and 20 to 45 parts of an initiator in 1000 to 2000 parts of a mixed monomer, and cooling the solution to obtain an oil phase for later use; mixing and homogenizing the aqueous phase and the oil phase with stirring to obtain a homogenized mixed solution; adding 300 to 550 parts of a foaming agent to the homogenized mixed solution and homogenizing the resulting solution with stirring to obtain a homogenized mixed solution containing the foaming agent; reacting the homogenized mixed solution containing the foaming agent with stirring; at the end of the reaction, cooling to room temperature, filtering the resulting suspension to obtain filtrate, centrifuging and dehydrating the filtrate, and drying to obtain the heat-expandable polyvinylidene chloride microsphere product. This disclosure has the advantages of simple process and environmental friendliness, and the obtained product has good performance.

Disclosed are a heat-expandable polyvinylidene chloride microsphere and its preparation method. The preparation method comprises: by weight, dissolving 250 to 550 parts of an aqueous-phase polymerization inhibitor, 20 to 100 parts of a dispersant, and 3 to 15 parts of a co-dispersing monomer in deionized water, adjusting a pH value of the solution and cooling the solution to obtain an aqueous phase for later use; dissolving 5 to 15 parts of a cross-linking agent and 20 to 45 parts of an initiator in 1000 to 2000 parts of a mixed monomer, and cooling the solution to obtain an oil phase for later use; mixing and homogenizing the aqueous phase and the oil phase with stirring to obtain a homogenized mixed solution; adding 300 to 550 parts of a foaming agent to the homogenized mixed solution and homogenizing the resulting solution with stirring to obtain a homogenized mixed solution containing the foaming agent; reacting the homogenized mixed solution containing the foaming agent with stirring; at the end of the reaction, cooling to room temperature, filtering the resulting suspension to obtain filtrate, centrifuging and dehydrating the filtrate, and drying to obtain the heat-expandable polyvinylidene chloride microsphere product. This disclosure has the advantages of simple process and environmental friendliness, and the obtained product has good performance.