稀土配位催化异戊二烯与极性单体共聚

【作者】 胡志国；

【导师】 张一烽； 沈之荃；

【作者基本信息】 浙江大学 ， 高分子化学与物理， 2001， 博士

【摘要】 系统研究了稀土配位催化剂催化异戊二烯（Ip）与极性单体如丙烯腈（AN）、1，2-氧化己烯（HO）、4-乙烯基吡啶（4-Vpy）的嵌段共聚，异戊二烯与马来酸酐（MAn）交替共聚，4-乙烯基吡啶的均聚，稀土固体超强酸催化八甲基环四硅氧烷（D₄）的开环均聚合。结果表明，稀土催化剂对上述（共）聚合反应具有优良的催化性能。 系统研究了稀土膦酸盐-烷基铝-活化剂（给电子体）组成的三元体系催化异戊二烯-丙烯腈嵌段共聚合。给电子体以1，2-二溴乙烷（DBE）为最佳。加料方式对共聚合影响很大，只有采用顺序聚合法即Ip在一定条件下聚合完全后，再加入AN聚合，才能合成相应的嵌段共聚物，而其它加料方式只能得到丙烯腈的均聚物。例如Nd(P₂₀₄)₃-Al（i-Bu）₃-DBE催化体系，最适宜的聚合条件为：[Nd]=0.01mol/L，Al/Nd=15（molar ratio），Br/Nd=3.0（molar ratio），甲苯溶剂，Ip：50℃聚合1hr，AN：60℃聚合7hr。所得嵌段共聚物有两个玻璃化转变温度（Tg分别为-75℃，96.3℃），有优良的耐溶剂性和较好的力学性能。含28.2％丙烯腈的嵌段共聚物（生胶）的断裂强度为0.53MPa，屈服强度为0.50MPa，断裂伸长率为261％，弹性模量为1.86MPa。 详细研究了三元稀土催化剂Nd(P₂₀₄)₃-Al（i-Bu）₃-DBE催化异戊二烯与1，2-氧化己烯的嵌段共聚合，其最佳聚合条件为：[Nd]=2×10^-3mol/L，Al/Nd=10（molarratio），Br/Nd=3（molar ratio），甲苯为溶剂，采用顺序聚合法，Ip聚合：50℃，5hr，HO聚合：70℃，48hr。用¹H-NMR、IR、GPC等分析表明所得产物为异成二烯与1，2-氧化己烯的嵌段共聚物。 首次将异戊二烯与1，2-氧化己烯嵌段共聚物用干固定化酶的研究。用电化学吸附法固定葡萄糖氧化酶于该共聚物中，制成异戊二烯/1，2-氧化己烯嵌段共聚物葡萄糖氧化酶电极。该电极有较好的稳定性，系统研究了电位、pH值、温度、底物浓度及其它金属离子对酶电极响应电流的影响。研究发现，该电极呈现典型的酶催化反应动力学特征。电极反应受扩散控制。固定葡萄糖氧化酶的表观米氏常数为32.2mmol/L，酶催化反应的活化能为37.2kJ/mol。 Nd(P₂₀₄)₃-Al（i-Bu）₃-DBE三元稀土催化剂用于异戊二烯与4-乙烯基吡啶嵌段 一 共聚合。其最佳聚合条件为：［IP卜卜VPy］＝Zmol几，［MI、l／［Nd卜1000，l／Nd叫 （molar ratio），Bibed二3（molar ratio），甲苯为溶齐，采用)I匝序聚合法，lp聚合： 50℃，3h，4Vpy聚合：30℃，4h。经革取纯化的聚合物的 h、‘H－N’’－－－和‘℃。N’MR 分析表明该聚合物为异戊二烯－4乙烯基毗唆的嵌段共聚物。 稀上络合物与烷基铝组成的二元稀土催化剂在甲苯／二氧六环混合溶剂中能 催化异戊二烯－马来酸团交替共聚。研究催化剂各组分、溶剂等对共聚合的影响 发现，不同配体的钛化合物活性次序为：Nd加aPh)。＞＞Ndo。J。“NdL们山” ＊＊＊C＊C)；·2民0＞＊＊＊＊＊0③。。不同稀土的环烷酸体系＊n（l ＊p＊。催化活性顺 序为：＊d＞Pr＞L＞sm＞Er。不同烷基金属化合物作共催化剂活性顺序为：A阳t。＞＞ AI（i－Bu）。＞ AIH（i－Bu）。＞ Mg（n－Bu）。。以甲苯／H氧六环（体积比为 2／5）为溶齐 时，共聚物收率较高。例如 Nd…。－AIEt。甲苯／二氧六环体系，适宜的共聚合 反应条件为：【M】总二2．6mO凡（厂卜【MAn】＝l），川fNd＝且mol＊f f＆tio），pd］＝SX10’ mol几，5℃聚合Zhr，共聚物收率达70％左右。所得共聚物的摩尔组成比与投 料比无关，其比值均为 ll。共聚物的h，‘℃－hJ－＊mH＊ DSC等分析表明该共聚物 为马来酸配打开C＝C双键与异戊二烯共聚合形成的交替共聚物。 Nd（川）。－烷基铝组成的二元稀土催化剂可以使个乙烯基毗陡聚合制得高分 子量（Mll为20－90万）的4－乙烯基毗睫均聚物。研究发现，以P删为配体的不 同稀土元素的催化活性次序为：Nd－Sin－Ho－Dy－La＞Pf－Er＞＞丫不同烷 基铝作共催化剂活性次序为：Al（SU）厂AIH（卫ll）户＞AIEt。。溶剂对聚合转化率 影响次序为：二氯甲烷＞甲苯－苯＞正己烷＞＞四氢吠哺。对于＊O加小－A队h)； 体系，最适宜的聚合条件为：＊VPy］＝0＊lmol／L，＊VPyl／［Nd］－1500，AIMd－10 （molar ratio），CH＊CI＊溶齐，30口C聚合 30min，转化率为 100％口用 o‘H一N’’r－r， ’℃－N’’n－＊ DSC ＆征了均聚物结构。 稀上固体超强酸用于八甲基环四硅氧烷开环聚合具有良好的催化活性，其 效率可达61kgPD4／moINd，催化剂重复使用两次，活性不变。经反复试验表明， 稀上固体超强酸在400巧00℃下焙烧具有较高?更多还原

【Abstract】 Copolymerizations of isoprene(Ip) with polar monomers - acrylonitrile(AN), l,2-epoxyhexane(HO), 4-vinylpyridine(4-Vpy), maleic anhydride(MAn) and homo-polymerizations of 4-vinylpyndine and octamethyl cyclotetrasiloxane(D4) by rare earth coordination catalyst or rare earth solid superacid have been studied for the first time. It has been found that rare earth catalyst has high catalytic activity for all polymerizations above-mentioned.Block copolymerization of isoprene and acrylonitrile by rare earth catalyst composed of rare earth phosphonate, alkyl aluminum and electron donor has been studied in detail. Rare earth catalyst combined by 1,2-dibromoethane as electron donor was the most active catalyst. The copolymer can be obtained only after the certain monomer-feeding mode which Ip has been polymerized for a certain time before adding AN. Otherwise, AN homopolymer will be obtained. The optimum conditions for Ip-AN copolymerization with Nd(P204)3-Al(i-Bu)3-DBE catalytic system are as follows: [Nd]=0.01mol/L, Al/Nd= 15 (molar ratio), Br/Nd=3.0(molar ratio), toluene as solvent, Ip polymerization: 50癈,lhr; AN polymerization: 60癈, 7hr. The poly(Ip-b-AN) has two glass transition temperatures (Tg: -75.6癈, 96.5癈), excellent solvent-resistance and good mechanical property. It’s breaking strength, yield strength, elongation and elastic modulus (AN content: 28.2%) are 0.53MPa, 0.50MPa, 261% and 1.86MPa, respectively.Block copolymerization of isoprene and 1,2-epoxyhexane by Nd(P204)3-Al(i-Bu)3-DBE catalyst has been investigated. The preferred conditions are: [Nd]=2x10-3mol/L, Al/Nd=10(molar ratio), Br/Nd=3 (molar ratio), toluene as solvent, sequence addition mode of feed, Ip: 50癈, 5hr; HO: 70癈, 48hr. Using the techniques of ER, ’H-NMR, GPC, the resultant copolymer has been characterized and proved to be blockcopolymers.The poly(Ip-b-HO) was used to immobilize glucose oxidase by electrochemical method for the first time. The influences of electrical potential, pH, temperature, substrate concentration and metal ion on the response electric current of the enzyme electrode have been studied. The poly(Ip-b-HO) glucose oxidase electrode has good operation stability , has typical kinetic characteristics and a diffusion controlled reaction. The apparent Michaelis constant and activation energy for the immobilized glucose oxidase are 32.2mmol/L and 37.2kJ/mol, respectively.Nd(P204)3-Al(i-Bu)3-DBE catalytic system is also effective catalyst for block copolymerization of isoprene with 4-vinylpyridine.The optimal conditions are as follows: [Ip]=[4-Vpy]=2moVL, [M]tol/[Nd]=1000, Al/Nd=15(molar ratio), Br/Nd = 3 (molar ratio), toluene as solvent, sequence feeding method, Ip. 50癈, 3hr, 4-Vpy: 30癈, 4hr. The Ip/4-Vpy block copolymer was characterized by IR, ’H-NMR.Alternating copolymerization of isoprene with maleic anhydride was carried out by rare earth coordination catalyst for the first time. The catalytic activity of various rare earth elements in Nd(naph)3 and ligands in NdL3 and organometallic compounds for the copolymerization has respectively the following order: Nd > Pr> La > Sm > Er; Na(naph)3 ?Nd(P204)3 > Nd(P507)3 > Nd(acac)3-2H20 > Nd(CF3COO)3; AlEt3 ?Al(i-Bu)3 > AlH(i-Bu)3 >Mg(n-Bu)2. The polymer yield is 70% with Nd(naph)3-AlEt3 catalytic system at following conditions: [M]to|=2.6mol/L ([Ip]=[MAn]=l), Al/Nd = 10(molar ratio), [Nd]=5xlO~3mol/L, toluene/dioxane=2/5(volume ratio) as solvent, 5癈, 2hr. The different feed ratios between Ip and MAn always result in the formation of a 1:1 copolymer.Homopolymer of 4-vinylpyridine with high molecular weight (Mr|: 20-90x104) was synthesized by rare earth coordination catalyst. The catalytic activity of various rare earth elements in Nd(P204)3 and alkylaluminum for copolymerization has respectively the following order: Nd ~ Sm ~ Ho ~ Dy ~ La > Pr ~Er 籝, Al(i-Bu)3 ~ AlH(i-Bu)2 ?AlEt3. Catalytic activity in various solvent shows follows sequence: dichloromethane > toluene ~ benzene > cyclohexane ?THE The monomer conversion is 100% by Nd(P204)3-Al(i-Bu)3 c更多还原