【作者】 殷勤俭；

【导师】 傅强；

【作者基本信息】 四川大学 ， 材料学， 2007， 博士

【摘要】 聚对苯二甲酸乙二醇酯（PET）是由对苯二甲酸和乙二醇通过缩聚反应生成的一种含芳环的饱和聚酯。虽然PET自问世以来主要都是被用于纺制纤维，应用于服装领域，但由于PET在较宽的温度范围内能保持优良的物理性能，抗冲击强度高、耐摩擦、刚性好、硬度大、吸湿性小、尺寸稳定性好、电性能优良、无毒无臭、加工方便、制件的外观洁净透明，能耐绝大多数有机溶剂和无机酸的腐蚀等，使它在非纤维用途方面的应用更为广泛。特别是近十年来，由于PET生产的大规模化，成本不断下降，PET在包装瓶、薄膜、工程塑料领域的应用更是得到了飞速的发展。但是，PET仍然存在一些固有的缺陷，使之难以得到应有的发展和应用。例如，PET的气体阻隔性和耐热性问题，由于PET对气体的阻隔性不够高（易使被包装物变质，所包装商品的货架期短）、热变形温度低（不能进行巴氏消毒）、耐挂擦伤能力差等，而不能用于氧活性商品（如啤酒、生化药品）的包装。其次是PET的抗静电性问题，由于PET的比电阻较高、摩擦电压大、极容易产生静电，而且静电半衰期长，在作为涤纶纤维和薄膜使用时，严重影响其加工性能和使用性能。再次是在工程塑料应用领域的问题，在芳香族聚酯中PET是性价比最高的，也是应用最为广泛的一种聚酯。但是，作为工程塑料使用时PET有三个重大缺陷：制品的尺寸稳定性差、熔体强度低、结晶速度慢，使PET的加工难度较大，加工时模具温度高达130℃以上，不能满足工业上快速注塑成型的需要。本研究就是针对PET目前急需解决的问题，从调整聚合物的分子结构着手，用工业上合成PET的通用方法（PTA法）合成了几种改性的功能性PET复合材料，提高了PET的耐热性、气体阻隔性和抗静电性。为了实现这一研究目的，本研究首先从合成手段开始，解决目前在实验室用酸法合成PET的重大困难，自行设计制造了一套微型聚酯合成反应装置，在实验室模拟工业生产，实现了酸法合成PET。该装置将工业上PET合成时的打浆、高压酯化、低真空缩聚、高真空缩聚等多步反应，通过科学设计和创造性改进，合并到一个反应装置中完成，在实验室实现了用一个反应釜合成PET及其共聚物的设想。该装置创造性地设计了一个“Y”形分支管，连接两个真空通路系统，一个通路用于低真空缩聚时进一步分离反应组分，提高单体转化率；另一个通路用于终缩聚时实现高真空度的缩聚反应。装置设计的“丁”字形堵针放料口，成功地解决了高真空密封和高粘度流体放料难的问题。该装置还具有微型化、多功能化的特点，既可以用于液相合成反应，也可以用于液—固—气多相反应，达到了一釜多能，一釜多用的功能，为今后实验室进行PET的改性研究提供了有力的“武器”。由于目前对高气体阻隔性高分子材料的研究还处于起步阶段，研究手段非常有限，特别是对高气体阻隔性材料(气体透过率小于3.8cm³．mm／m²．24h．MPa≈19×10^-5cm³．20μm／m²．d．Pa)的气体透过率的测试手段还相当落后，现有的测试仪器几乎都不能准确测定高气体阻隔性材料的气体透过率。本文设计制造了一套KWY-02型高阻隔性材料气体透过率测定仪，采用一些先进的设计思想和工业技术，成功地解决了这一难题。通过仪器配件的合理配置，可以测试很宽范围内材料的透气率，测试范围可以覆盖漏率为1.0×10^-2cm³．20μm／m²．d．Pa～10^-8cm³．20μm／m²．d．Pa的薄膜材料。KWY-02型气体透过率测定仪在透气室上创造性地设计了一个螺盖式关启装置，使测试操作变得简单、快捷，而且可靠性好。仪器的适用范围广，可以测定常见的所有非腐蚀（腐蚀金属）性气体；仪器运行时无污染（不使用水银压力计），自动化程度高，稳定性好。本文用间苯二甲酸（IPA）与对苯二甲酸、乙二醇在高温、高压下进行酯化反应，发现IPA的加入使整个酯化反应的诱导期缩短了，体系中IPA占的比例越高，酯化反应的诱导期越短，发生酯化反应的温度越低；而缩聚时却相反，体系中IPA的含量越高，缩聚的诱导期越长，100％的间苯二甲酸—双—β—羟乙酯（BHIT）缩聚的诱导期长达200mins，但缩聚温度比对苯二甲酸—双—β—羟乙酯（BHET）缩聚时低。IPA改性的PEIT的结晶性变差了，PEIT的结晶度随IPA含量的增加而降低，当IPA的含量达到18％时共聚酯的冷结晶峰和熔融峰几乎都消失了，到20％wt的含量时就完全看不到了，含20％IPA的PEIT是完全的无规共聚物。低IPA含量（≤10％）的PEIT力学性能随IPA含量的增加而有所增加，当IPA的含量大于10％以后，共聚酯的力学性能又开始降低。甘油可以与PTA在高温高压下发生酯化反应生成相应的甘油酯，但如果反应体系中有乙二醇存在，甘油与PTA的酯化反应就难以进行，只能通过甘油与BHET的酯交换反应生成相应的单甘油酯。甘油组分对聚酯（PET）的性能影响很大，低甘油含量（≤2％wt）的共聚酯（PEGC）中仍存在少量游离的伯羟基，它使共聚酯的力学性能、气体阻隔性增加，但结晶性变差；当甘油的含量超过2％以后，缩聚反应变得困难，体系的粘度迅速增大，而聚合物的分子量却难以增长，得到的是完全非晶态的共聚酯，其力学性能随甘油含量的增加而迅速降低，难以加工成型。本文合成了一系列的耐热性环状羟烷基吗啉铵盐，如吗啉盐酸盐、羟乙基吗啉盐酸盐、羟丙基吗啉盐酸盐、N-（1．1-二甲基-羟乙基）吗啉盐酸盐、N-（6-羟己基）吗啉溴化铵和N-（10-羟癸基）吗啉溴化铵，其中N-（6-羟己基）吗啉溴化铵和N-（10-羟癸基）吗啉溴化铵的热分解温度超过360℃。这几种环状羟烷基吗啉铵盐都能与Na-MMT发生阳离子交换，进入到MMT的层间，使MMT的层间距增大，N-（6-羟己基）吗啉溴化铵和N-（10-羟癸基）吗啉溴化铵可以使MMT的层间距扩大到20 （?）以上。在180℃时乙二醇锑在乙二醇中的溶解度可以达到15.8％，这时乙二醇锑在改性MMT上的吸附（负载）量最大，达到6％wt（以MMT的量计）。用负载有乙二醇锑的有机化MMT与BHET反应制得的PET—MMT复合材料在MMT的含量低于2％时为纳米复合材料。复合材料的冷结晶温度比纯PET降低了6.3℃，熔点比纯PET升高了8.5℃；最大热失重温度比纯PET升高了114℃，提高到590℃；薄膜材料对氧气的阻隔性提高了3倍，但力学性能有所下降。用强氧化剂（浓硝酸、浓硫酸和H₂O₂的混合物）氧化的方法，使CNTs的尾端或侧壁发生氧化反应，生成“活性”的羧基或羟基，可以提高MWNT在极性溶剂中的分散能力，这种功能化的MWNT在乙二醇和水中分散性好，稳定性高，室温放置2周也没有分层。用超声处理和溶剂驱替的方法，将功能化的MWNT均匀地分散到乙二醇中，然后再与PTA在高温高压酯化、缩聚制得了PET-CNTs纳米复合材料。在PET中，MWNT的含量低于0.1％时可以达到纳米级的均匀分散，而含量大于0.2％wt时就不能形成均匀分散了。MWNT在PET起到成核剂的作用，加速了PET的结晶。少量的MWNT可以提高PET的力学性能，添加0.05％的MWNT可以使PET的断裂强度由48.2MPa提高到61.1MPa，模量由2.21GPa提高到2.52GPa，断裂伸长率也由274％提高到了318％。MWNT能显著提高PET的导电性能，而且随MWNT含量的增加PET的导电性也随之提高，当MWNT含量为0.05％时，PET的导电率提高了2个数量级，因此，MWNT可以作为PET的抗静电剂。但是，MWNT在PET基体中存在一个临界聚集浓度点，约为0.2％。在此浓度下，MWNT在PET基体中分散较好，但PET分子链易在MWNT上折叠结晶，形成一层包裹层，对PET-CNTs纳米复合材料的导电率提高不是很大。大于此浓度后，MWNT就开始缠结成团，在PET中的分散性变差，使PET的力学性能降低；但如果MWNT的量增大到一定程度（≥3.0％wt），纳米管之间就可能形成“搭接”，管与管之间逐渐导通，使PET-CNTs复合材料的电阻率发生突变。更多还原

【Abstract】 Poly（ethylene terephthaltae） （PET） is one kind of saturated polyester contained aromatic ring, which is condensed from terephthalic acid and glycol. PET is mainly being made to fibred products widely, used for cloth and garment since it was invented. But for the excellent PET can resist the etching against to most of organic solvent and inorganic acid, and it has not only high impact strength, outstanding insulation, little moisture absorption, but also avirulence, flavourless, wearable and rigid properties, it can be easily process to products with good stabilization in a broad temperature range, PET has been used in more field as non-fiber application. Especially, the application of PET in packaging bottle, film and engineering plastic which has been developed quickly recent ten years.However, there some inherent disadvantage of PET hold it back been used more widely and progress properly. For example, PET can not be used as especial packaging materials to contain the merchandise which have sensitivity for oxygen （such as beer and biochemical medicine） for it has no high gas barrier and heat-resistant properties. Secondly, PET has a great resistivity, triboelectricity voltage and long time of electrostatic half life; it can bring electrostatic charge easily to the membrane and fibre, influence badly to application and manufacture progress. Thirdly, PET is the finest aromatic polyester with lowest price, top-quality and widest application, but there have three mainly limitations restricted it’s utility in engineering plastic which was PET crystallize slowly, the size of PET products can not stabilize for enough time, and there no enough tension strength of PET melting to process expediently. For this reason, the mould of PET produce in process must attains to 130℃, it can not to be manufacture by injection quickly in PET industry. This research work focused on the imperative problem of PET, designed a special molecular structure of modified PET, synthesized and modified a several functional PET materials by means of PET industrial manufacture ways （PTA technique）, to improve PET’ properties of heat-resistant, gas barrier and antistatic.To finish this objective, above all, a set of mini reactor was designed and manufactured by ourselves, in which PET can be synthesized as industrial manufacture ways （PTA technique） in the laboratory. Four different steps of reaction technics in synthesizing PET progress such as making PTA and EG to be pasty, esterification reaction in high press, condensation reaction in lower vacuum and condensation reaction in the lowest vacuum would be actualized in this one equipment, PET and co-PET also be synthesized in one unit as this facility in the laboratory.A branch tube shape like "Y" was designed and fixed on the mini reactor, it connects two passageways together. Condensation reaction in lower vacuum was realized in one pipeline in which product and material can be separated completely, and condensation reaction in the lowest vacuum was realized in another pipeline. A "T" needle was designed and fixed on the exit down below the mini reactor, it can seal reactor easily in the state of lowest vacuum and take the PET product with high viscosity out off the reactor after the synthesis reaction. Not only the liquefacient reaction but also liquid- solid- gaseous reaction can be actualized in this mini reactor. It is a sharp "weapon" to research PET and functional PET in laboratory at present and future.For there few ways to test the quality of gas barrier on barrier polymer materials, especially to the particular type of polymer which has lowest gas permeability (the rate of gas transmission is lower than 3.8 cm³. mm/m².24h.MPa≈19 x10^-5 cm³. 20μm / m². d. Pa ). One set of gas permeation meter named KWY-02 was invented in this work, it can test the rate of gas transmission accurately to most of polymer films which gas permeability is froml.0 x10²cm³. 20μm/ m.2. d. Pa to 10^-8cm³. 20μm/m². d. Pa.A screw cap switch was devised and installed on the KWY-02 gas permeation meter; make it can be operated simply, quickly and automatically. Most of gas’ permeability in polymer film can be measured on this set （except corrosive gas）. There no pollution for the pressure gauge without mercury. Inductive time of esterified reaction between the terephthalic acid and ethylene glycol under high pressure and temperature was shortened by additional isophthalic acid（IPA）. By contrary, inductive time of condensation reaction of isophthalate-bis-β-hydroxide ethyl ester （BHIT） was retarded by the amount of IPA. Inductive time of condensation reaction of pure BHIT reached to 200mins, but the temperature of condensation reaction was lower than terephthalate-bis-β-hydroxide ethyl ester （BHET）. The cooling crystal peak of co-polyester of PTA, IPA and ethylene glycol （PELT） contains 20%wt IPA was disappeared, it means that PEIT with 20%wt IPA is random copolymer. The mechanical properties of PEIT improve with the content of IPA, it becomes badly when the content of IPA over 10%.PTA and glycerol will become to glyceride under high pressure and temperature by esterification reaction, but it is impossible that esterification reaction while there some glycol and glycerol exist in same system. BHET and glycerol can become to glyceride by ester interchange reaction. There is a little dissociative first hydroxyl group in the co-polyester of terephthalic acid, glycol and glycerol （PEGC）, which improve the mechanical properties and gas barrier. When the amount of glycerol exceed over 2%, it becomes very difficult that polymerization reaction of terephthaltae acid, glycol and glycerol.A several heat stability organic hydroxyl alkyl ammonium with morpholine ring were synthesized in this work, such as hydrochloric morpholine salt, 4-morpholineethanol hydrochloric salt,α-methyl-4-morpholineethanol hydrochloric salt, N-（1,1-dimethyl- hydroxyl ethylene） morpholine hydrochloric salt, N-（6- hydroxyl hexane） morpholine ammonium bromide and N-（10- hydroxyl decane） morpholine ammonium bromide. The heat decompose temperature of N-（6- hydroxyl hexane） morpholine ammonium bromide and N-（10- hydroxyl decane） morpholine ammonium bromide go beyond 360℃. They can come into the interior of montmorillonite （MMT） layer by cation exchange reaction, expands the distance of MMT layer. The distance of MMT layer can be distended to more than 20A by N-（6- hydroxyl hexane） morpholine ammonium bromide and N-（10- hydroxyl decane） morpholine ammonium bromide.15.8% weight of antimony glycol could be dissolved in glycol at 180℃, and adsorbed on MMT for 6%. PET-MMT nanocomposite was condensation polymerized from BHET and MMT loaded antimony glycol, the cooling crystal temperature of PET-MMT nanocomposite with 2% of MMT falls to 130.2℃from136.5℃of virgin PET; the melt point climbs to 264.5℃from 246℃of pure PET, the onset temperature of degradation is about 114℃higher for nanocomposite; oxygen barrier ability is three times than origin PET, but mechanical properties goes to the bad.Oxidation reaction is took place on the parietal wall or the tail of carbon nanotubes （CNTs） in the solution of forceful oxidizer （such as the mixture of thick nitric acid, oil of vitriol and H202）, a few active group of hydroxide or carbonyl are generated in this reaction, it can improve the solubility of multi wall carbon nanotubes （MWNT） in polar solvents. The stability of the mixture of functional MWNT and glycol or water prolongs to two weeks. PET-CNTs nanocomposite was in situ polymerized from PTA, glycol and functional MWNT which has been treated with ultrasonic and dispersed equably to glycol.MWNT can be dispersed equably to PET while the content below 0.2%, it acts as nucleus of crystal to PET. The strength at break of PET-CNTs nanocomposite with 0.05% MWNT increases to 61.1MPa from48.2MPa of virgin PET; modulus improves to 2.52GPa from2.21MPa of origin PET and the elongation at break attains to 318%.Electric conductivity of PET-CNTs nanocomposite film is improved with the content of MWNT. 100 times of electric resistance for PET is higher than PET-CNTs nanoeomposite with 0.05% MWNT which acts as anlistatig to PET. There is a critical point of MWNT content in PET that is about to 0.2%. Molecular chain of PET can crystallize on MWNT which can dispersed equably in PET while the content of MWNT below 0.2%, there is little improvement of electric conductivity for PET-CNTs nanocomposite film. On the other hand, MWNT will tangle to each other and couldn’t to be dispersed equably in PET while the content of MWNT beyond to 0.2%, affects availably electric conductivity of PET-CNTs nanocomposite film.更多还原