Styrene-butadiene copolymer as well as preparation and applications thereof

[0065] Example 1

[0066] Add 2.5 liters of a mixture of cyclohexane and raffinate (the mixing ratio of cyclohexane and raffinate is 9:1) into a 5-liter polymerization vessel purged with nitrogen, and the content in the polymerization solvent is 300 mg/kg Add tetrahydrofuran in the same amount. The mixture was heated to 50° C., 100 g of styrene was first added, and then 1.0 mmol of n-butyllithium was added to initiate the reaction. After stirring and reacting for 20-60 minutes, 150g of butadiene was added to the living polymer, during which the reaction temperature was controlled at 40-115°C, the reaction was stirred for 20-60min, and then 5ml of water was added to terminate the reaction. Add 0.2-0.6% antioxidant based on the mass of the polymer to the reaction mixture, and stir for 5 minutes. Finally, the product is added to a mixture of steam and water, the solvent is evaporated, and the polymer is isolated in a solid state and suspended in water. Separate the solids, squeeze water with an extrusion dehydrator, and devolatilize in a drying box to obtain a linear structure of styrene-butadiene copolymer. The molecular weight of this copolymer is 290,000 (Mn). In this polymer, styrene and butadiene are polymerized in a block manner. The NMR and GPC spectra are shown respectively figure 1 , figure 2.

[0072] Example 2

[0073] Add 2.5 liters of a mixture of cyclohexane and raffinate (the mixing ratio of cyclohexane and raffinate is 9:1) into a 5-liter polymerization vessel purged with nitrogen, and the content in the polymerization solvent is 300 mg/kg Add tetrahydrofuran in the same amount. The mixture was heated to 50°C, and 2.15 mmol of n-butyllithium was added. After stirring for 5 minutes, 162.6 g of butadiene monomer was added to the polymerization vessel, during which the reaction temperature was controlled at 40-110°C, and the reaction was carried out for 20-60 minutes. Then 75g of styrene is added to the reaction kettle, and the reaction is carried out for 20-60 minutes. Then add 12.4g of butadiene to the reaction kettle, react for 5-30 minutes, and finally add 5ml of coupling agent silicon tetrachloride, react for 10-40 minutes, add 0.2-0.6% of the antioxidant based on the mass of the polymer to the mixture. Oxygen, stir for 5 minutes. Finally, the product is added to a mixture of steam and water, the solvent is evaporated, and the polymer is isolated in a solid state and suspended in water. Separate the solids, squeeze water with an extrusion dehydrator, and devolatilize in a drying box to obtain a star-shaped styrene-butadiene copolymer. The molecular weight of the copolymer is 400,000 (Mn). The nuclear magnetic spectrum and GPC spectrum are shown respectively image 3 , Figure 4.

[0082] Example 3

[0083] 0.48 kg of the linear structure styrene-butadiene copolymer of Example 1 of the present invention is uniformly mixed with 6 kg of general-purpose polystyrene, and added to the twin-screw extruder to form HIPS particles. The temperature of the twin-screw machine is 140°C.