【作者】 喻桂朋；

【导师】 王植源； 蹇锡高；

【作者基本信息】 大连理工大学 ， 高分子材料， 2009， 博士

【摘要】 芳基均三嗪环聚合物具有优异的耐热性能、高强度、高模量、高阻燃性、良好的化学稳定性及独特的光学和电学性能。但传统芳基均三嗪环聚合物难溶解、难熔融,通常在高温高压下才能制得高分子量聚合物,限制了其在一些领域如绝缘漆、涂料及分离膜等的应用。本文设计合成了氰基封端含二氮杂萘酮联苯结构聚芳醚,并实现了分子链中氰端基在常压条件下三聚生成均三嗪环的交联固化反应;以含芳基均三嗪环双氟单体和二氮杂萘酮联苯酚单体等为原料,进行溶液亲核取代缩聚反应,制备了系列既耐高温又可溶解主链含芳基均三嗪环结构新型聚芳醚。首先分别以对氟苯腈、对氯苯腈和对氰基苯甲酸等为原料,以氯化锌（ZnCl₂）或氯磺酸等路易斯酸为催化剂,考察了氰基在常压条件下进行三聚环化反应的可行性。在类似反应条件下,分别以对苯二腈（TPH）、联苯二腈（DCB）为原料,在300℃进行本体聚合反应48 h,制得两种聚芳基均三嗪。优化了反应体系、温度、时间、催化剂种类和含量等工艺条件,结果表明,对于氰基在常压下的环化反应,ZnCl₂是较为合适的催化剂,TPH和DCB聚合转化率最高分别可达82%和78%。以对苯二酚（HQ）、间苯二酚（RS）和联苯二酚为原料,分别与对氯苯腈进行亲核取代反应,合成了三种较低熔点的含醚键二腈,并分别研究了其在优化条件下的聚合反应。自制二腈聚合转化率均低于60%,低于TPH和DCB的转化率,说明吸电子对位取代基有利于氰基的三聚反应。上述合成的聚合物均不溶于有机溶剂,其结构通过FTIR、元素分析等手段得到了证实。为解决芳香族二腈聚合产物成型加工难等问题,将扭曲非共平面的二氮杂萘酮联苯结构引入到氰基聚合物分子主链中,以期获得具有良好溶解性、可进行交联反应的聚合物。以4-（4-羟基-苯基）（2氢）-二氮杂萘-1-酮（HPPZ）与2,6-二氟苯腈为原料,进行亲核取代缩聚反应,通过控制聚合单体配比,合成了聚芳醚腈（PPEN）和N-H末端的齐聚物（PPEN-OL）。用FT-IR、DSC、TGA、WAXD和溶解性等方法考察了合成的含氰侧基聚合物在常压下的交联反应活性,结果表明在ZnCl₂和TPH存在下,PPEN和PPEN-OL在氮气中360℃热处理6 h时结构稳定,说明氰侧基难以反应。为提高氰基活性,以对氯苯腈为原料,对PPEN-OL进行封端,设计合成了含氰端基的聚芳醚腈（PPEN-DC）;以含二氮杂萘酮联苯结构二酸单体与4,4’-二氨基二苯醚为原料,经Yamazaki膦酰化缩聚,并用对氰基苯甲酸进行封端,合成了含氰端基的聚芳醚酰胺（PPA-DC）。所合成的聚合物均可溶于NMP、DMAc和DMF等极性有机溶剂中。PPEN-DC和PPA-DC在常压下交联反应活性的研究表明:经类似热处理后,氰端基发生三聚环化反应生成芳基均三嗪环。PPEN-DC交联后T_g>360℃,提高了97℃以上,氮气气氛下5%热失重温度(T_d5%)高于515℃,提高了30℃以上;PPA-DC交联产物在100～450℃的DSC扫描未检测到T_g,氮气气氛下T_d5%高于469℃,提高了10℃以上。为提高氰基含量和活性,设计合成了含二氮杂萘酮联苯结构的双邻苯二甲腈单体（Ph-HPPZ）和邻苯二甲腈封端聚芳醚。首先以4-硝基邻苯二甲腈（NPh）与（4-苄基苯基）-2,3-二氮杂萘-1-酮的亲核取代反应为模型反应,研究了其反应机理。采用类似反应条件,HPPZ与NPh反应合成了Ph-HPPZ,优化了温度、时间、反应物浓度和比例等工艺条件,Ph-HPPZ的收率和纯度最高分别可达96%和98%。Ph-HPPZ分别与少量芳香二胺或TPH和ZnCl₂反应制备了预聚物。单体和预聚物均可溶于DMSO、NMP、DMAc和DMF等极性有机溶剂,且可在常压下进一步固化制得含芳基均三嗪环聚合物。为进一步改善加工性能,合成了邻苯二甲腈封端含二氮杂萘酮联苯结构聚芳醚腈/砜/酮及其共聚物。封端聚合物分别与少量芳香二胺或TPH和ZnCl₂反应制备了B阶树脂。封端聚合物和B阶树脂均可溶于CHCl₃、DMSO、NMP、DMAc和DMF等极性有机溶剂,并具有良好的成膜性,并可在芳香二胺或TPH和ZnCl₂存在下,常压条件下固化生成含芳基均三嗪环聚合物。采用TPH为固化剂时,有利于提高固化产物中芳基均三嗪环结构的含量。固化物均在100～450℃的DSC扫描未检测到T_g,并具有优异热稳定性(氮气中:T_d5%>506℃,800℃时残碳率C_y>73%;空气中:T_d5%>505℃)。为改善传统含苯基均三嗪环聚芳醚（PAEPs）的溶解性,以2,4-二（4-氟苯基）-6-苯基-1,3,5-三嗪（BFPT）和间苯二酚（RS）、双酚S或HPPZ为原料,经溶液亲核取代缩聚反应,制备了三种PAEPs。PAEPs在室温下可溶于NMP和DMAc,并具有优异的耐热性能(T_g>243℃;氮气中:T_d5%>536℃;空气中:T_d5%>529℃)。以BFPT、对苯二酚（HQ）和RS为原料,制备了一系列更高热稳定性的PAEPs无规共聚物。共聚物在室温下可溶于NMP、DMAc和DMF等,其T_g（241～248℃）变化符合Fox方程,氮气中T_d5%高于575℃,空气中T_d5%高于541℃。为进一步改善PAEPs溶解性,设计合成了四种含苯基均三嗪环和取代型二氮杂萘酮联苯结构聚芳醚（PPEPs）。PPEPs在室温下可溶于NMP、DMAc和Py等,其T_g均高于255℃。以HPPZ、BFPT和DCS为原料,合成了一系列含苯基均三嗪环和二氮杂萘酮联苯结构聚芳醚砜无规共聚物（PPESPs）。PPESPs在室温下可溶于NMP、DMAc、DMF、Py和CHCl₃等。其T_g值（271～300℃）随苯基均三嗪含量增加而下降,而结晶度和热失重温度(T_d5%>503℃)随之升高。各聚合物薄膜样品均具有良好的机械性能。利用TG和DTG研究了各聚合物在氮气气氛下的热分解动力学,并推导了热分解机理。线型含苯基均三嗪环聚芳醚比商品聚芳醚具有更高的分解活化能,说明苯基均三嗪的引入可赋予聚合物优异的耐热性能。更多还原

【Abstract】 Conventional phenyl-s-triazine-based polymers are well-known for their outstanding comprehensive properties including excellent thermal stability, high strength and modulus, good flame retardance and chemical resistance, unique electronic and optical properties. However, such polymers always exhibit no melt or soften temperatures and poor solubility, and high-molecular-weight polymers are frequently prepared at high temperatures under high pressures. Therefore, it is difficult to process these polymers, which hampers their widespread application as insulting coatings, adhesives and membranes. Starting from the design in molecular structure, soluble cyano-terminated poly（phthalazinone ether）s were synthesized and thermally crosslinked to afford new phenyl-s-triazine polymers by the trimerization of cyano groups under normal pressure; new series of soluble and heat-resistant poly（aryl ether phenyl-s-triazine）s were synthesized by the nuleophilic displacement polymerization of phenyl-s-triazine-containing dihalides with 4-（4-hydroxylphenyl）（2H）-phtha-lazin-1-one monomers.The trimerization of 4-fluorobenzonitrile, 4-chlorobenzonitrile （CBN） and 4-cyanobenzoic acid （CBA） in the catalysis of ZnCl₂ or ClSO₃H under normal pressure were initially conducted as model reactions to investigate the cyclization reactivity of aromatic mono-nitriles. Two kinds of poly（pheny-s-triazine） networks were respectively prepared by the bulk polymerization of terephthalonitrile （TPH） and 4,4’-dicyanobiphenyl （DCB） under similar conditions. The cyclization conditions were optimized with respect to reaction system, time, temperature, catalyst nature and its content, and ZnCl₂ is found to be more suitable than other catalysts investigated for the trimerization of aromatic nitriles under normal pressure, and the maximum conversations of terephthalonitrile （TPH） and 4,4’-dicyanobiphenyl （DCB） were 82% and 78%, respectively. Four kinds of aromatic ether-linked dinitriles with low melting temperatures were obtained via the nucleophilic substitution of hydroquinone （HQ）, resorcinol （RS）, biphenol and bisphenol A with CBN. They were polymerized to afford a series of poly（pheny-s-triazine）s under the optimized conditions. The conversations （below 60%） of these polymerization reactions are much lower than those of TPH and DCB, indicating that the trimerization is favorably promoted by the activation of strong electron-withdrawing substitutents in the para-orientation. The resulting polymers were insoluble in orangnic solvents and their structure was confirmed by FTIR, elemental analysis and other measurements.Cyano-containing polymers were designed and supposed to trimerize to afford phenyl-s-triazine rings, and crank and twisted phthalazinone moieties were also incorporated into the polymer backbone to impart good solubility, with a viewing to improving the processability of the phenyl-s-triazine-based polymers. Poly（phthalazinone ether nitrile）s （PPENs） and their oligomers with N-H ends （PPEN-OL） were synthesized by the solution polycondensation of 2,6-difuorobenzonitrile with calculated 4-（4-hydroxylphenyl）（2H）-phtha-lazin-1-one （HPPZ）. FT-IR, TGA, WAXD and solubility measurements demonstrated that PPENs and PPEN-OL hardly underwent any crosslinking after thermal treatment at 360℃for 6 h under normal pressure, even in the presence of TPH and ZnCl₂. To improve the cyano reactivity, cyano-terminated PPENs （PPEN-DC） were prepared by the end-capping reaction of PPEN-OL with CBN; benzonitrile terminated poly（phthalazinone ether amide）s （PPA-DC） were also prepared by the polycondensation of excess 4,4’-oxydianiline with 1,2-dihydro-2-（4-carboxyphenyl）-4-[4-（4-carboxyphenoxyl）phenyl]-phthalazinone, followed by end-capping with CBA. The polymers synthesized exhibited good solubility in NMP, DMAc and DMF, and were crosslinked to afford phenyl-s-triazine-containing polymers under the similar conditions. T_gs of crosslinked PPEN-DC, which are increased at least by 94℃upon thermal crosslinking, are higher than 360℃, and T_d5% values （>515℃） are increased at least by 30℃upon crosslinking. The crosslinked PPA-DC exhibit no T_g up to 400℃as edvienced by DSC, and T_d5% values （>469℃） are increased at least by 10℃upon thermal crosslinking.Phthalazinone-containing bisphthalonitrile and phthalonitrile-terminated polymers were synthesized to increase the crosslinkable group content and their reactivity. The nucleophilic displacement of 4-（4-tolyl）（2H）-phthalazin-1-one with 4-nitrophthalonitrile （NPh） was investigated as a model reaction and the reaction was confirmed to proceed via a novel N-C coupling reaction. The reaction of HPPZ with NPh conducted in similar conditions as for model reaction readily afforded phthalazinone-based bisphthalonitrile （Ph-HPPZ） in high yields. The effect of temperature, time periods, reactant concentration and ratio on the yield and purity of Ph-HPPZ was also investigated and the maxium yield and purity are 96% and 98% under optimal conditions, respectively. Ph-HPPZ was polymerized to form a prepolymer （B-stage resin） in the presence of diamines or a mixture of TPH and ZnCl₂. Both monomer and its prepolymer exhibit good solubility in CHCl₃, DMSO, NMP, DMAc and DMF, and can be thermally cured to afford phenyl-s-triazine-based thermosets under normal pressure. Phthalonitrile-terminated PPENs, PPESs, PPEKs and their copolymers, were respectively synthesized via nucleophilic displacement reactions of HPPZ with activated dihalides and NPh in similar conditions. They were polymerized to B-stage resins in the presence of aromatic diamines or a mixture of TPH and ZnCl₂. The phthalonitrile-terminated polymers and B-stage resins are readily soluble in NMP, DMAc, DMF, DMSO and chloroform, and exhibit good film-forming properties. Additonally, they can be directly advanced to phenyl-s-triazine-based networks under normal pressure. The addition of TPH increases the phenyl-s-triazine content in the produced networks. The networks exhibit no detectable T_g up to 400℃and show excellent thermal stability (N₂: T_d5%>509℃, C_y>73%; Air: T_d5%>505℃).To improve the organosolubility of conventional poly（aryl ether phenyl-s-triazine）s （PAEPs）, three kinds of new PAEPs were prepared by the nuleophilic displacement polymerization of 2,4-bi（4-fiuorophenyl）-6-phenyl-1,3,5-triazine （BFPT） with RS, 4,4’-dihydroxydiphenyl sulfone and HPPZ, respectively. The obtained polymers were readily soluble in NMP and DMAc at room temperature, and exhibited high thermal stabilities and oxidative stabilities (T_gs>243℃; N₂:T_d5%>536℃; Air: T_d5%>529℃). Similarly, a new series of copoly（aryl ether phenyl-s-triazine）s were synthesized via the polycondensation of BFPT with various ratios of HQ and RS. A good agreement of T_g values （ranging from 241～248℃） of the copolymers with values predicted by Fox equation was also observed and they exhibit excellent thermal stability (N₂: T_d5%>575℃; Air: T_d5%>541℃). Four kinds of poly（aryl ether phenyl-s-triazine）s containing alkyl-, aryl- and chloro-substituted phthalazinone moieties （PPEPs） were prepared through solution polycondensation of BFPT with substituted phthalazinones. The T_gs of resulting polymers are ranging from 255-265℃. A new series of copoly（phthalazinone ether sulfone phenyl-s-triazine） were prepared starting from HPPZ, BFPT and DCS in similar procedures. The copolymers exhibit better solubility in NMP, DMAc, DMF and Py than the polymers described above. Their T_gs （271～300℃） increase with an increase in sulfone content in the polymer main chain, while the crystallinity and overall thermal stability appear to decrease. All films of the polymers synthesized possess good mechanical properties in the ambinent temperatures. The apparent activation energy （E_a） of the produced polymers was detemined under N₂ flow in dynamic heating conditions and the decomposition mechanism was also proposed. The E_a values of the obtained polymers are much higher than that of the commercial available poly（aryl ether）s, suggesting their superior thermal stability due to the incorporation of phenyl-s-triazine rings.更多还原