用負(fù)載型Z-N催化劑制備形貌規(guī)則的空心球形聚乙烯粒子
發(fā)布時(shí)間：2018-08-23 08:22
【摘要】：采用一種含二酯類內(nèi)給電子體的氯化鎂負(fù)載Ziegler-Natta催化劑和三異丁基鋁(TIBA)助催化劑,在同一反應(yīng)器中經(jīng)常壓丙烯預(yù)聚和加壓下的乙烯與少量丙烯淤漿共聚合兩步反應(yīng),高效地合成了外徑為0.4~3 mm的中空球形聚乙烯粒子,其球形粒子的外表面和內(nèi)部空腔的內(nèi)表面均較為平滑,殼層厚度均勻.聚合反應(yīng)的催化劑效率最高達(dá)到7.49 kg/g Ti·h·MPa(6.5 kg PE/g Cat.).研究了助催化劑種類、助催化劑濃度(Al/Ti摩爾比)和乙烯聚合階段的丙烯共單體添加量對(duì)聚合物粒子形貌的影響,發(fā)現(xiàn)采用三乙基鋁(TEA)或TEA/TIBA混合物為助催化劑時(shí),雖然聚合物粒子仍呈中空球形形態(tài),但其內(nèi)部空腔的形狀極不規(guī)則.以TIBA為助催化劑時(shí),在一定范圍內(nèi)提高Al/Ti比和丙烯添加量均可顯著提高催化效率,聚合反應(yīng)動(dòng)力學(xué)曲線由衰減型變?yōu)樵鲩L(zhǎng)型,但聚合物粒子的中空形貌得以保持.對(duì)比丙烯預(yù)聚產(chǎn)物的粒子形貌發(fā)現(xiàn),助催化劑含TEA時(shí)所得預(yù)聚物粒子結(jié)構(gòu)較松散,內(nèi)部有較多孔隙和裂紋,而改為T(mén)IBA后預(yù)聚物粒子內(nèi)部相對(duì)致密.
[Abstract]:A magnesium chloride supported Ziegler-Natta catalyst and triisobutyl aluminum (TIBA) co-catalyst were used in the two-step copolymerization of ethylene with a small amount of propylene slurry in the same reactor. Hollow spherical polyethylene particles with an outer diameter of 0.4 ~ 3 mm were synthesized efficiently. The outer surface of the spherical particles and the inner surface of the inner cavity were smooth and the shell thickness was uniform. The catalyst efficiency of polymerization is up to 7.49 kg/g Ti h MPa (6.5 kg PE/g Cat.). The effects of the type of co-catalyst, the concentration of co-catalyst (Al/Ti molar ratio) and the amount of propylene monomer in ethylene polymerization on the morphology of polymer particles were studied. It was found that when the mixture of triethylaluminum (TEA) or TEA/TIBA was used as co-catalyst, Although the polymer particles are still hollow spherical, the shape of the inner cavity is extremely irregular. When TIBA was used as the co-catalyst, the catalytic efficiency could be significantly improved by increasing the ratio of Al/Ti and the amount of propylene in a certain range. The kinetics curve of polymerization changed from attenuated type to growth type, but the hollow morphology of polymer particles was maintained. Comparing with the morphology of propene prepolymer, it was found that the structure of the prepolymer was looser, and there were more pores and cracks in the prepolymer when the catalyst contained TEA, but the prepolymer particle was relatively dense after the change to TIBA.
【作者單位】： 浙江大學(xué)高分子科學(xué)與工程學(xué)系高分子合成與功能構(gòu)造教育部重點(diǎn)實(shí)驗(yàn)室;
【基金】：國(guó)家自然科學(xué)基金(基金號(hào)21374094) 國(guó)家高技術(shù)研究發(fā)展計(jì)劃(863計(jì)劃,項(xiàng)目號(hào)2012AA040305)資助項(xiàng)目
【分類號(hào)】：O643.36;TQ325.12
本文編號(hào)：2198472
[Abstract]:A magnesium chloride supported Ziegler-Natta catalyst and triisobutyl aluminum (TIBA) co-catalyst were used in the two-step copolymerization of ethylene with a small amount of propylene slurry in the same reactor. Hollow spherical polyethylene particles with an outer diameter of 0.4 ~ 3 mm were synthesized efficiently. The outer surface of the spherical particles and the inner surface of the inner cavity were smooth and the shell thickness was uniform. The catalyst efficiency of polymerization is up to 7.49 kg/g Ti h MPa (6.5 kg PE/g Cat.). The effects of the type of co-catalyst, the concentration of co-catalyst (Al/Ti molar ratio) and the amount of propylene monomer in ethylene polymerization on the morphology of polymer particles were studied. It was found that when the mixture of triethylaluminum (TEA) or TEA/TIBA was used as co-catalyst, Although the polymer particles are still hollow spherical, the shape of the inner cavity is extremely irregular. When TIBA was used as the co-catalyst, the catalytic efficiency could be significantly improved by increasing the ratio of Al/Ti and the amount of propylene in a certain range. The kinetics curve of polymerization changed from attenuated type to growth type, but the hollow morphology of polymer particles was maintained. Comparing with the morphology of propene prepolymer, it was found that the structure of the prepolymer was looser, and there were more pores and cracks in the prepolymer when the catalyst contained TEA, but the prepolymer particle was relatively dense after the change to TIBA.
【作者單位】： 浙江大學(xué)高分子科學(xué)與工程學(xué)系高分子合成與功能構(gòu)造教育部重點(diǎn)實(shí)驗(yàn)室;
【基金】：國(guó)家自然科學(xué)基金(基金號(hào)21374094) 國(guó)家高技術(shù)研究發(fā)展計(jì)劃(863計(jì)劃,項(xiàng)目號(hào)2012AA040305)資助項(xiàng)目
【分類號(hào)】：O643.36;TQ325.12
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