PET钛系催化剂的应用进展

聚酯钛系催化剂催化活性高,对环境友好,能够使PET具有更高亮度和透明性,但也具有催化稳定性差、加剧副反应,使合成的PET色相变差、性能指标下降等缺点。通过对国外的一些钛系催化剂产品和对国内学者的钛系催化剂应用研究的简要说明,介绍了PET钛系催化剂应用发展的现状。随着聚酯工业的发展以及人们的环保意识的提高,具有高反应活性的不含重金属的钛系催化剂的开发应用,目前已经成为聚酯缩聚催化剂发展的趋势,有着光明的应用前景。     

耐水解钛系催化剂评价研究

用一种新型的耐水解钛系催化剂A145合成聚酯(PET),考察了在PET合成中A145的催化效果,并与传统的钛系催化剂钛酸四丁酯进行了对比,确定了A145的加入时机与加入量。结果表明:A145可取代传统的钛系催化剂来合成PET。     

钛锑复合催化剂聚酯切片的结晶性及可纺性

通过差示扫描量热分析和X射线衍射分析等研究了钛锑复合催化剂生产的聚对苯二甲酸乙二醇酯(PET)切片的结晶性能及其可纺性。结果表明:与常规锑系催化剂生产的PET切片相比,钛锑复合催化剂生产的PET切片的结晶速度慢,结晶度低,熔体降温结晶温度有所下降,冷结晶温度有所上升,可纺性好;钛锑催化剂的PET纤维的力学性能优于常规锑系催化剂的PET纤维。     

钛系催化剂的瓶级PET切片工程化生产

应用钛系聚酯催化剂LT181在25万t连续缩聚PET生产线工程化生产瓶级PET切片。对切片的特性黏度、端羧基值、色值、乙醛含量、二甘醇含量进行检测分析,钛系催化剂能取得和锑系催化剂相似的技术指标。     

钛系催化剂对PET酯化反应的影响探讨

使用2l反应釜,详细考察了自制钛系催化剂和PET酯化反应的相互影响情况,钛系催化剂在较高反应温度和含水量的酯化反应条件下聚合反应活性不降低,同时对酯化反应过程有促进作用,最后介绍了钛系催化剂在工业装置上对酯化反应影响的应用状况。     

液体钛系催化剂合成PET的研究

在5 L聚合釜上评价研究液态钛系催化剂,确定催化稳定体系包括液态钛催化剂添加量、反应温度的选择,切片热性能和制备的PET性能进行分析。制备合格的环境友好型无锑PET。     

环保型钛系催化剂简介及在PET装置的应用

简要介绍了新型环保型钛系催化剂,及采用环保型钛系催化剂的必要性;环保型钛系催化剂的调制,以及在投用过程中通过对工艺及产品品质的控制,特别针对色相上升加入调色剂,实现钛系催化剂4∶6取代锑催化剂。     

基于SWOT分析的钛系聚酯的开发及应用

运用势态(SWOT)分析方法,对国内钛系聚酯的开发应用从优势、劣势、机遇和挑战4个方面进行了全面分析,结合国内外钛系聚酯产品的发展现状,提出了国内聚酯行业加快发展钛系聚酯的建议。钛系催化剂属于环保型高效催化剂,钛系聚酯性能优良,但钛系聚酯的发展还不成熟,尚存在技术和市场风险;建议我国应以钛系催化剂进行聚酯技术革新,加强研发、生产和市场的有机结合,制订和完善钛系聚酯产品的技术标准,培育和扩大钛系聚酯产品的应用市场,加快推进钛系聚酯的工业化。     

钛系聚酯催化剂的工业应用进展

随着人们对环境保护、生态平衡等意识的提高,钛系聚酯产品作为一种环保产品也应运而生,同时推动了钛系聚酯催化剂的开发与应用。本文主要叙述了钛系聚酯催化剂的研制思路及开发进程,介绍了钛系聚酯催化剂的国内外工业应用状况,指出了应用环保性钛系聚酯催化剂是开发差别化聚酯产品的一个重要方向。     

钛系催化剂在半消光聚酯生产中的应用

在300 t/d聚酯(PET)装置上通过减少锑系催化剂添加量,逐步将钛系催化剂添加比例由15%提高至100%,最终实现钛系催化剂生产环保型PET产品,分析了钛系催化剂替代量对PET切片质量、热性能以及过滤器切换周期的影响。结果表明:随着钛系催化剂替代比例的提高,PET切片色相b值大幅上升,将酯化Ⅰ釜温度由264℃下降至256℃,酯化Ⅱ釜温度由268℃下降至259℃,增大调色剂添加量控制在30μg/g以内,可保证色相L值不低于90;将预聚釜Ⅰ温度由271℃下降至265℃,预聚釜Ⅱ温度由276℃下降至274℃,终缩聚温度由278℃下降至276℃,可将端羧基含量控制在指标要求范围;将酯化Ⅰ釜压力由65k Pa提高至79 k Pa,工艺塔釜温由175℃提高至178℃,可缓解二甘醇含量下降幅度,但对二甘醇含量提高效果不明显;全钛系PET比全锑系PET降温峰值温度低13.66℃,降温峰值温度与冷结晶温度之差低20.29℃,有利于纺丝;全钛系PET生产中过滤器切换周期比全锑系PET的长。     

低熔点PET的制备

在常规PET生产中加入适当的第三单体和第四单体可制备低熔点聚酯。以精对苯二甲酸(PTA)和乙二醇(EG)为原料,加入适当的间苯二甲酸(或己二酸)、1,4-丁二醇(或6-己二醇),聚乙二醇的质量分数(相对二元羧酸)为5％～8％,采用质量分数为0.005％～0.008％钛系催化剂,生产的低熔点聚酯熔点为110～120℃,且热稳定性好。     

PET synthesis in the presence of new aluminum catalysts

A new polycondensation catalyst (ethylene glycol aluminum) was synthesized and applied in PET synthesis. It has been characterized by spectral studies (IR, NMR). The catalytic activity of organic aluminum compound was discussed in this paper. In this investigation, the synthesis of poly(ethylene terephthalate) (PET) is presented using ethylene glycol (EG) and terephthalic acid (TPA). The result proved that ethylene glycol aluminum was the real catalytic material. And it was proved to be the most efficient catalyst for the polycondesation reaction among the organic aluminum compounds. Similar catalytic activity has been observed for ethylene glycol aluminum compared to ethylene glycol antimony. The esterification reaction was monitored by measuring the distilled water as a function of time and the modeling of this process was carried out from these data. The received PET samples were characterized by viscometry, carboxyl end-group content and diethylene glycol (DEG) content. A mechanism of aluminum catalysis has been proposed to explain these observations.     

高效催化剂对切片性能的影响

研究了在1万t/a连续聚酯装置上使用高效催化剂合成的半消光切片的相对分子质量及其分布、结晶性能、流变性能以及热稳定性能，并与相同装置由常规催化剂合成的切片相对比。高效催化剂与常规催化剂制备切片具有相同的相对分子质量及其分布、结晶机理和流变性能。2种催化剂制备切片的热分解稳定性基本相同，高效催化剂制备切片的热降解稳定性略逊于常规催化剂切片，但可以满足纺丝加工要求。从总体上看，使用高效催化剂不会影响切片的内在质量。     

金催化剂在丙烯气相直接环氧化反应中的应用

环氧丙烷（PO）是一种重要的有机化工原料。近来发现采用沉积-沉淀法将金高度分散在一些含钛物质表面上时,能够催化H2-O2-丙烯气相体系直接合成PO。金粒大小和分散状态,载体及助剂等因素对催化剂性能有重要影响。主要就催化剂性能的影响因素,反应及失活机理等方面的研究进展情况进行了总结和评述,以利于将来深入地研究。     

Study of the reactions occurring during melt mixing of poly(ethylene terephthalate) and polycarbonate

In this work the reactions taking place during melt mixing of bisphenol-A polycarbonate (PC) with poly(ethylene terephthalate) (PET) were studied by selective degradation of PC sequences, solubility tests, and IR spectroscopy. It was found that exchange reactions between PC and PET took place, contrary to what has been previously suggested by other authors. Kinetic constants were evaluated from intrinsic viscosity measurements of PET blocks. The reaction rate was slow when only the Sb catalyst (residues of the PET polymerization) were present, but it was significantly accelerated by the addition of Ti(OBu)₄. In the presence of the latter catalyst, other side reactions, leading to discoloration and gas evolution, took place.     

草酸亚锡体系中对PET稳定剂的研究

本文研究了草酸亚锡体系中几种单一稳定剂和复合稳定剂对PET副反应的抑制。采用磷酸、磷酸酯类或亚磷酸、亚磷酸酯类作为稳定剂,均能提高PET的热稳定性,改善树脂的质量指标;与酚类抗氧剂一起作为复合稳定剂,效果更佳。较好的草酸亚锡体系与实用的三氧化二锑体系的比较,表明在实际生产中草酸亚锡作为缩聚催化剂是很有前途的。     

Characterization of self-standing Ti-containing porous silica thin films and their reactivity for the photocatalytic reduction of CO2 with H2O

Self-standing porous silica thin films with different pore structures were synthesized by a solvent evaporation method and used as photocatalysts for the photocatalytic reduction of CO₂ with H₂O at 323 K. UV irradiation of these Ti-containing porous silica thin films in the presence of CO₂ and H₂O led to the formation of CH₄ and CH₃OH as well as CO and O₂ as minor products. Such thin films having hexagonal pore structure exhibited higher photocatalytic reactivity than the Ti-MCM-41 powder catalyst even with the same pore structure. From FTIR investigations, it was found that these Ti-containing porous silica thin films had different concentrations of surface OH groups and showed different adsorption properties for the H₂O molecules toward the catalyst surface. Furthermore, the concentration of the surface OH groups was found to play a role in the selectivity for the formation of CH₃OH.     

Photo-induced super-hydrophilic property and photocatalysis on transparent Ti-containing mesoporous silica thin films

The transparent Ti-containing mesoporous silica thin films can be prepared on quartz plate using a spin-coating sol–gel method. The spectroscopic characterization has revealed that the Ti-containing mesoporous silica thin films contain isolated and tetrahedrally-coordinated titanium oxide moieties in the frameworks. Compared with the common mesoporous silica thin films, these Ti-containing mesoporous silica thin films have demonstrated a strong hydrophilic surface property even before UV-irradiation. After UV-light irradiation, the contact angle of water droplet on the Ti-containing mesoporous silica thin films became lower, indicating the appearance of the super-hydrophilic property. Under UV-light irradiation Ti-containing mesoporous silica thin films also exhibited highly selective activity for the photocatalytic oxidation of propylene. The isolated and tetrahedrally-coordinated titanium oxide moieties are responsible for these photo-induced surface reactions.     

Crystallization kinetics of polyethylene terephthalate. I. Isothermal crystallization from the melt

The crystallization behavior of polyethylene terephthalate (PET) was investigated as a function of molecular weight, temperature of crystallization, and polycondensation catalyst system. A detailed analysis of the crystallization course has been made utilizing the Avrami expression. The crystallization rate constants and the Avrami exponents were calculated. The results show that the rate constant and the mechanism of crystallization are dependent on the molecular weight, temperature, and the polycondensation catalyst system. The catalyst system often exhibits a more significant influence than the molecular weight in controlling the rate of crystallization of PET.     

Melting and crystallization behavior of poly(ethylene terephthalate) and poly(m‐xylylene adipamide) blends

The crystallization and melting behaviors as well as the crystalline morphologies of Poly(ethylene terephthalate)/Poly(m‐xylylene adipamide) (PET/MXD6) blends have been examined and characterized with the aid of differential scanning calorimetry (DSC) and wide angle x‐ray diffraction (WAXD). The isothermal and nonisothermal crystallization behaviors of the blends were studied as functions of the contents of MXD6, catalyst concentrations, and the effects of the interchange reactions between PET and MXD6. Wide angle x‐ray scattering has been used to examine the crystalline morphologies of the PET/MXD6 blends, to characterize their crystalline and amorphous phases, and to determine crystallite sizes in the blends. Results indicate that the catalyst has both catalyzing and nucleation effects on the PET/MXD6 blends, with the extents of each effect dependent upon the content of catalyst. In addition the crystalline morphology was found to be dominated by the MXD6 content as well as the crystallization temperature. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010