2,6-二甲基萘制备技术进展

综述了目前国内外制备2,6-二甲基萘的各种催化剂体系、工艺技术和研发状况,包括煤焦油和石油裂解重质芳烃的直接分离法;萘、甲基萘、甲苯、二甲苯等为原料的化学合成法以及二甲基萘的异构化法。通过比较其工艺特点和催化剂性能,指出以廉价、丰富的萘或甲基萘为原料与甲醇烷基化反应合成2,6-二甲基萘是当前最合理的技术路线;其中,高效催化剂的制备是关键,特别是以改性沸石分子筛为主的催化剂。     

2,6-二甲基萘技术现状及应用

概述了2,6－二甲基萘的技术现状,对4种合成方法的成本进行技术经济比较,并介绍了PEN在容器、薄膜、纤维及注塑材料中的应用。     

聚萘二甲酸乙二醇酯（PEN）生产技术进展

对PEN最新生产技术及由邻二甲苯和丁二烯为原料合成PEN的技术经济性作了综述。基于PEN的发展与其单体价格密切相关,指出降低2,6-DMN生产成本仍将是今后PEN生产技术改进的方向。     

2,6-二甲基萘氧化制备2,6-萘二甲酸的工艺研究

2,6-二甲基萘是重要的有机化工原料,通过对中质洗油进行精馏-结晶,可获得纯度达99.7%的2,6-二甲基萘。以从中质洗油提取的2,6-二甲基萘为原料,在高温高压反应釜中,研究了不同加料方式、反应温度、反应压力、催化剂浓度对氧化工艺的影响,结果表明,2,6-二甲基萘连续加料,在反应温度190℃,反应压力2.5 MPa,Co-Mn-Br浓度为1 500 ppm条件下,液相氧化效果最好,2,6-NDA收率为84.7%。     

2,6-二甲基萘的制备与分离技术进展

论述了由萘、甲基萘经选择性烷基化法及二甲基萘异构化法生成 2 ,6 -二甲基萘的研究进展 ;介绍了从萘系物中分离 2 ,6 -二甲基萘的方法 ,对压力结晶法做了较详细的阐述 ;指出从重油接触裂解柴油馏分中制备 2 ,6 -二甲基萘是石油萘生产的最理想的技术方向。     

2,6-萘二甲酸的合成与纯化技术进展

系统综述了萘二甲酸的国内外研究进展,详细介绍了各种合成与纯化方法,并同时分析了各个方法的优缺点及经济效益.     

2,6-二甲基萘的合成

研究了以甲基萘为原料采用转移甲基化法合成2,6-二甲基萘(2,6-DMN)的工艺条件。通过考察温度、反应时间、催化剂的种类及用量、转移甲基化试剂的用量、溶剂用量等因素对2,6-DMN收率的影响,探讨了转移甲基化法合成2,6-DMN的工艺条件。结果表明,2-甲基萘(2-MN)使用量为2 g 时,反应温度为18℃、时间为2．5 h、n(无水三溴化铝)∶n(2-甲基萘)=0．8、n(转移甲基化剂四甲苯)∶n (2-甲基萘)=1．0、二氯甲烷用量为15 mL时,2,6-DMN的收率可达38％。另外,采用GCMS对产物进行了表征。     

2,6-二甲基萘的制备技术

综述了2,6-二甲基萘提取和合成技术,包括从石油焦油、煤焦油直接提取技术和以萘、甲基萘、甲苯和二甲苯为原料的化学合成工艺,并对其进行了全面的介绍,同时比较了各种制备2,6-二甲基萘工艺的优缺点,指出邻二甲苯/丁二烯烷基化路线由于采用的原料充足,价格合理,适合大规模生产,因而具有很重要的开发前景。     

2,6-二甲基萘空气液相氧化制备2,6-萘二甲酸的研究

2,6-萘二甲酸（2,6-NDCA）及其衍生物是制备各种聚酯和聚氨酯材料的重要单体,在钛材间歇式搅拌釜中,以2,6-二甲基萘为原料,醋酸钴、醋酸锰、醋酸钾和溴化物等为催化剂,研究了2,6-二甲基萘空气液相氧化制备2,6-萘二甲酸的过程。确定n（Co＋Mn）/n（HAc）,n（Co）/n（Co＋Mn）,n（Br）/n（Co＋Mn）,n（Co＋Mn）/n（2,6-DMN）,n（K＋）/n（Co＋Mn）和助催化剂对收率和纯度的影响,从而得到比较适宜的催化条件。在此催化条件下,还考察了引发温度、反应压力、反应温度、溶剂比以及醋酸的浓度对收率和纯度的影响,确定了最佳合成2,6-萘二甲酸反应条件。     

转移甲基化合成2,6-二甲基萘研究

以β-甲基萘为原料,均四甲基苯为烷基化剂,在催化剂作用下,进行转移甲基化反应合成2,6-二甲基萘,考察了反应的温度,催化剂和烷基化剂的加入量对反应结果的影响。     

Mechanical,morphological, and thermal properties of poly(ethylene 2,6-naphthalate) and copolyester LCP blends

Binary blends of a liquid crystalline polymer (LCP) and poly(ethylene 2,6-naphthalate) (PEN) were melt blended and injection molded. The mechanical properties were studied as a function of LCP content. Both the ultimate tensile strength and Young's modulus are higher than the theoretical values predicted by the rule of mixtures and they display a synergistic behavior at 70 wt % LCP content. However, the tensile strength decreases with LCP content and Young's modulus remained unchanged at lower LCP contents (10 to 30 wt %). The poor mechanical property is attributed to the immiscibility between PEN and LCP and the fibrillation behavior of LCP as revealed by differential scanning calorimetry (DSC) and scanning electron microscopy (SEM) results. However, LCP and PEN are found to be partially miscible at higher LCP content, ascertained by DSC and dynamic mechanical analysis (DMA). This is attributed to the transesterification reaction between PEN and PET moiety in the LCP molecules. SEM micrographs reveal a skin/core morphology in the tensile bars, that is, the LCP is better oriented in the skin than in the core region. At lower LCP content, the dispersed LCP phase is spherical in the core and ellipsoidal in the skin, with long axes oriented in the flow direction. DSC studies show that the crystallization rate is significantly enhanced by the presence of LCP up to 50 wt %, where the LCP acts as a nucleating agent for PEN crystallization. The melting temperature decreases with LCP content, probably as a result of imperfect crystals formed in the presence of LCP heterogeneous nucleating centers and the increasing miscibility between LCP and PEN. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 477–488, 2001     

Rapid crystallization of poly(ethylene 2,6-naphthalate) via aryl amide derivatives

ABSTRACT

A very small amount of aryl amide derivative (TMB-5) was used for nucleating Poly(ethylene 2,6-naphathalate) (PEN) by melt blending. The crystalline temperature, crystallinity, and nucleation efficiency of the composites were increased as a result of the addition of TMB-5. The half-time of crystallization decreased upon the addition of TMB-5 and the work required in folding polymer chains were reduced simultaneously in the polymer mixtures. The crystal size of the PEN/TMB-5 blends became smaller due to the increase of nucleation sites. The TMB-5 had no effect on the PEN crystal type. TMB-5 slightly increased the impact strength of PEN.     

PEN/PET共混物结晶行为研究

用差示扫描量热法(DSC)研究了不同共混比例PEN/PET共混物的熔体结晶行为,并进行了等温结晶动力学测定。结果表明:随着两种组分向中间比例(50/50)靠近,共混物的熔融温度越低,结晶速率也越慢。     

Nanostructure of atmospheric and high-pressure crystallized poly(ethylene-2,6-naphthalate). Part II: structure-microhardness correlations

The microhardness of poly(ethylene naphthalene-2,6-dicarboxylate) (PEN), with a detailed characterized nanostructure has been investigated. PEN samples were crystallized from the glassy state at atmospheric pressure and from the melt at high pressure and were characterized using small-angle X-ray scattering (SAXS), wide-angle X-ray scattering (WAXS) and differential scanning calorimetry (DSC). Results show that the degree of crystallinity derived from WAXS, for both atmospheric and high-pressure crystallized PEN, is smaller than that obtained by density and calorimetry. For high-pressure crystallized samples, both, crystallinity and microhardness values are larger than those found for the material crystallized under atmospheric pressure. In the latter case, the hardness values depend on the volume fraction of lamellar stacks within spherulites X_L that depends on the crystallization temperature T_c. For T_c<200 °C, X_L is found to be less than 50%. Thus, for T_c<200 °C a linear relationship between H and T_c is observed provided a sufficiently long crystallization time is used. Results are discussed in terms of the rigid amorphous fraction that appears as a consequence of the molecular mobility restrictions due to the crystal stacks.     

Uniaxial orientation and tensile properties of poly(ethylene terephthalate)/poly(ethylene-2,6-naphthalate) blends

Amorphous films of poly(ethylene terephthalate)/poly(ethylene-2,6-naphthalate) (PET/PEN) blends with different blend ratios were uniaxially drawn by solid-state coextrusion and the structure development during solid state deformation was studied. As-prepared blends showed two T_gs. The lower T_g was ∼72 °C, independent of the blend ratio. In contrast, the higher T_g increased with increasing PEN content. Thus, the coextrusion was carried out around the higher T_g of the sample. At a given draw ratio of 5, which was close to the achievable maximum draw ratio, the tensile strength of the drawn samples from the initially amorphous state increased gradually with increasing PEN content. On the other hand, the tensile modulus was found to decrease initially, reaching a minimum at 40-60 wt% PEN, and then increased as the PEN content increased. The results indicate that we can get the drawn films with a moderate tensile modulus and a high tensile strength. The drawn samples from the blends containing 40-60 wt% of PEN showed a maximum elongation at break, and a maximum thermal shrinkage around 100 °C. Also, the degree of stress-induced crystallinity showed a broad minimum around the blend ratio of 50% of PEN. These morphological characteristics explained well the effects of blend ratio on the tensile modulus and strength of drawn PET/PEN blend films.     

不同制备方法所得PEN纤维的结构性能比较

利用高速纺丝法与纺丝拉伸一步法两种不同的方法制备聚萘二甲酸乙二酯 ( PEN)纤维 ,以DSC、X射线衍射、声速、力学测试等手段分析其结构、热学及力学性能并进行比较。结果表明 :以上两种纺丝法所制备 PEN纤维的晶型、晶粒尺寸不同 ;在所采用的高速纺丝速度范围内 ,分别以 6,7,8km/m in的速度纺制的试样结构性能基本相同 ;而纺丝拉伸一步法中不同的拉伸倍数对纤维的取向度影响较大 ,进而使杨氏模量、断裂强度和断裂伸长率变化较大     

2,6-萘二甲酸的合成进展

2,6-萘二甲酸（2,6-NDCA）及其衍生物是制备各种聚酯和聚胺酯材料的重要单体,其与乙二醇反应得到的聚2,6-萘二甲酸乙二醇酯（PEN）,具有优异的力学特性、化学特性和独特的热稳定性等特性,是一种新型高性能通用工程塑料。目前,由于2,6-萘二甲酸生产过程较复杂,生产成本很高,在一定程度上,限制了PEN的应用。因此开发合理的2,6-萘二甲酸合成路线,降低2,6-萘二甲酸制造成本,是国内外研究人员致力研究的方向。综述了国内外2,6-萘二甲酸的合成路线和制备方法。