尼龙1218的等温及非等温结晶动力学研究

采用示差扫描量热计DSC考察了一种新型长烷基链偶偶尼龙 尼龙 12 18 自熔体的结晶过程 ,分别利用Avrami方程和Ozawa方程对等温及非等温结晶动力学进行了描述与研究 ,计算了相关的结晶动力学参数 ,得出相应的结晶机理 .最后计算了等温结晶活化能和非等温结晶活化能 ,依此得到烷基链段长度与尼龙结晶过程有密切关系     

用调制式差示扫描量热法表征尼龙6和聚乳酸升温热行为

用调制式差示扫描量热法(MDSC)表征尼龙6和聚乳酸升温过程热行为，MDSC把总热流分解成可逆热流ΔHrev和不可逆热流ΔHnon;实验结果表明纯尼龙及其共混体系升温熔融过程中包含了可逆放热峰；共混体系不同，可逆热流ΔHrev不同，都比纯尼龙小；纯尼龙可逆热流ΔHrev随调制周期延长而增大；聚乳酸玻璃化转变区，随老化时间的延长和老化温度的提高，玻璃化转变温度Tg提高，松弛热焓增大。     

中孔分子筛MCM—41的合成与表征

以白炭黑和正硅酸乙酯为硅源，十二、十六烷基三甲基铵为模板剂，用水热法和室温直接法合成出中孔分子筛ＭＣＭ－４１，考察了对合成的影响因素，用红外光谱、吸附、孔分布、热分析等手段对这两种产物进行了表征。     

原位缩聚法制备碳纳米管/尼龙11复合材料

用原位缩聚法制备了碳纳米管增强的尼龙11复合材料,用X射线衍射仪、红外(FTIR)、扫描电镜(SEM)、热重(TGA)、机械拉伸测试仪等对其结构、形貌、热性能及机械性能进行了表征测试.扫描电镜结果显示碳纳米管均一地分散在尼龙11/碳纳米管复合材料中.复合材料的拉伸模量比纯尼龙11有较大的提高.当复合材料中碳纳米管含量分别为1%,5%,10%时,材料的拉伸模量分别提高了34.5%,92.9%和113,7%.同时,复合材料的储能模量也有提高.热分析结果显示当复合材料中碳纳米管含量为1%时,其失重5%和10%的温度分别由纯尼龙11的404℃、424℃提高到414℃和437℃.示差扫描量热分析(DSC)显示复合材料的结晶温度随碳纳米管的加入而升高,而结晶度则降低.     

聚对苯甲酰胺存在下尼龙6的结晶化

用解偏振光强度法和DSC等方法研究了少量聚对苯甲酰胺(PBA)对尼龙6结晶化过程和热行为的影响.利用Avrami方程处理解偏振光强度法的实验结果,得到了尼龙6及含PBA 1%、2%尼龙6的n值分别为3.3、1.6、1.7.DSC结果表明,尼龙6中掺入少量的PBA会使结晶度提高,X射线衍射显示,当尼龙6中加入少量PBA后,晶格结构并未改变。     

半芳香共聚酰胺的合成及热稳定性的研究

采用熔融缩聚法, 合成了长碳链聚酰胺(PA1212)与聚对苯二甲酰十二碳二胺(PA12T)的新型半芳香共聚酰胺, 用FTIR, 1H NMR和DSC对产物结构进行了表征. 通过热重分析研究了共聚酰胺在N2气氛中以不同升温速率β升温时的热降解过程与机理. 结果表明PA1212/12T的降解为一步过程, 随着β的增大, 平衡降解温度线性升高. 用Kissinger和Flynn-Wall-Ozawa两种方法求得PA1212/12T的热降解表观活化能分别为126.9和127.9 kJ/mol. 用Coats-Redfern法证明了PA1212/12T的热降解机理为Deceleration类型中的R1或F3降解机理.     

TiZSM—48型分子筛的快速合成及性能

在Na_2O-1.6-C_6H_(14)N_2-SiO_2-TiO_2-H_2O体系中首次用快速动态法和静态法合成了TiZSM-48型分子筛,考察了两种合成方法的晶化动力学。利用XRD、IR、XPS、SEM、DRS、TG-DTA等测试手段对TiZSM-48型分子筛进行了表征,结果表明,Ti进入了分子筛骨架,动态法合成比静态法合成快得多,且样品的晶粒较小。热分析表明,两种方法合成的样品热稳定性均较好。     

聚对氧化偶氮苯酚酯系列热致性液晶高分子的合成及液晶态研究

本文用界面缩聚法合成聚对氧化偶氧苯酚酯系列热致性液晶高分子。并用DSC,X-光衍射和偏光显微镜对其结构和液晶相进行了表征与研究。观察液晶态织态结构,计算液晶态时分子链间距,并观察聚合物取向液晶态的结晶结构。     

羧酸稀土配合物共聚反应的研究

通过沉淀法和直接法制备羧酸稀土配合物，与丙烯酸等单体共聚反应制备不同稀土含量的稀土有机高分子离聚物。用微量热天平(TG)、差热分析仪(DTA)等分析它的热稳定性以及玻璃化转变温度，用红外光谱分析其结构。讨论了用不同方法合成的稀土配合物对共聚反应和聚合物性能的影响。结果显示直接合成羧酸稀土配合物有利于共聚物性能的稳定和稀土含量的调节。     

两种有机溶胶法合成铬酸镧超细粉体的对比研究

用两种有机溶胶法——Pechini法和低温燃烧法分别合成了铬酸镧超细粉体。借助红外光谱（ATR）、热分析（TG，DSC）、X射线衍射等手段对制备的凝胶结构、热分解过程、粉体结构和形貌进行对比分析。结果得出，羟基作为最主要的络合基团存在于两种合成方法的凝胶中。虽然两种方法的反应过程相似，但燃烧法只经过一步燃烧就可以迅速合成最终粉体，Pechini法必须经过较长时间煅烧。燃烧法得到的粉体粒径小于Pechini法，分散性也较好。另外，还讨论了两种合成方法反应过程及产物形态差别的原因。     

Temperature-induced changes in chain-folded lamellar crystals of aliphatic polyamides. Investigation of nylons 2 6, 2 8, 2 10, and 2 12

Four members of the even-even nylon 2 Y series, for Y = 6, 8, 10, and 12, have been crystallized in the form of chain-folded lamellar single crystals from 1,4-butanediol and studied by transmission electron microscopy (imaging and diffraction), x-ray diffraction, and thermal analysis. The structures of these 2 Y nylons are different from those of nylon 6 6 and many other even-even nylons. At room temperature, two strong diffraction signals are observed at spacings 0.42 and 0.39 nm, respectively; these values differ from the 0.44 and 0.37 nm diffraction signals observed for nylon 6 6 and most even-even nylons at ambient temperature. Detailed analyses of the diffraction patterns show that all these 2 Y nylons have triclinic unit cells. The diamine alkane segments of 2 Y nylons are too short to sustain chain folds; thus, the chain folds must be in the diacid alkane segments in all cases. On heating the crystals from room temperature to the melt, the triclinic structures transform into pseudohexagonal structures and the two diffraction signals meet at the Brill transition temperature which occurs significantly below the melting point. The room temperature structures of these 2 Y nylons are similar to the unit cell of nylon 6 6 at elevated temperature, but below its Brill temperature. The room temperature structures and behavior on heating of the nylon 2 Y family is noticeably different from that of the even-even nylon X 4 family, although the only difference between these families of polyamides is the relative disposition of the amide groups within the chains. The results show that in order to understand the structure, behavior and properties of crystalline nylons, especially as a function of temperature, the detailed stereochemistry needs to be taken into account. © 1997 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys, 35: 675–688, 1997     

Investigation of solution‐grown,chain‐folded lamellar crystals of the even‐even nylons: 6 6, 8 6, 8 8, 10 6, 10 8, 10 10, 12 6, 12 8, 12 10, and 12 12

Chain‐folded lamellar crystals of the ten even‐even nylons: 6 6, 8 6, 8 8, 10 6, 10 8, 10 10, 12 6, 12 8, 12 10, and 12 12 have been grown from solution and their morphologies and structures studied using transmission electron microscopy, both imaging and diffraction. Sedimented mats were examined using X‐ray diffraction. The solution‐grown crystals are lath‐shaped lamellae and diffraction from these crystals, at room temperature, reveals that three crystalline forms are present in differing ratios. The crystals are composed of chain‐folded, hydrogen‐bonded sheets, the linear hydrogen bonds within which generate a progressive shear of the chains (p‐sheets). The sheets are found to stack in two different ways. Some p‐sheets stack with a progressive shear, to form the “α_p structure”; others sheets stack with an alternate stagger, to form the “β_p structure”. Both the α_p and β_p structures give two strong diffraction signals at spacings of 0.44 nm and 0.37 nm; these signals represent a projected intrasheet interchain distance (actual value 0.48 nm) and the intersheet spacing, respectively. Preparations of nylons 6 6, 8 6, 8 8, 12 6, and 12 8 consisted almost entirely of α_p‐structure material, with only a trace of β_p‐structure material being present. In contrast, nylons 10 6, 10 8, 10 10, 12 10, and 12 12 contained substantial quantities of both α_p‐ and β_p‐structure material, with α_p‐structure material always being in the majority. Preparations of nylons 10 8, 12 10, and 12 12 also showed an additional diffraction signal at 0.42 nm; this signal is characteristic of the pseudohexagonal (high temperature) structure. The melting temperature of solution‐grown lamellae of these even‐even nylons decreases with decreasing linear amide density. On heating, the strong diffraction signals (0.44 nm and 0.37 nm) gradually moved together and merge at the Brill temperature to form a single diffraction signal (0.42 nm), characteristic of the pseudohexagonal structure. This single diffraction signal remained until melting. For nylons 6 6, 8 6, 8 8, 10 6, and 12 6, the Brill temperatures were substantially below the respective melting temperatures and the single 0.42 nm diffraction signal was stable over temperature ranges of 14 °C to 56 °C, depending on the nylon. Conversely, nylons 10 8, 10 10, 12 8, 12 10, and 12 12 had coincident melting and extrapolated Brill temperatures. © 2000 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 38: 1209–1221, 2000     

固相缩聚法制备高粘度尼龙1111

采用固相缩聚工艺提高尼龙1111的相对粘度,是制备高粘度尼龙1111的有效方法之一。固相后缩聚法制备相对粘度高于2.5的高粘度尼龙1111,宜选择初始相对粘度为2.0的尼龙1111,反应时间12h,反应温度175℃。增粘后的尼龙1111具有更为优良的物理机械性能。     

Structures of X 34‐nylons in chain‐folded lamellae and gel‐spun fibers

Structural studies and morphological features of a new family of linear, aliphatic even–even, X 34‐nylons, with X = 2, 4, 6, 8, 10, and 12, are investigated with X‐ray diffraction and electron microscopy. Solution‐grown crystals were obtained by isothermal crystallization from N,N‐dimethylformamide solutions. The thickness of lamellar‐like crystals was orders of magnitude less than the chain lengths of the polymer samples used, implying that the chains fold to form chain‐folded lamellae. The results bear a close resemblance, with the noticeable exception of 2 34‐nylon, to those reported for nylon 6 6 and other even–even nylon chain‐folded lamellar crystals. The basic structure of the straight‐stem lamellar core is similar to that of the classic nylon 6 6 triclinic α structure, and the chains tilt ≈42° relative to the lamellar normal. In the case of 2 34‐nylon, the structure resembles the 2 Y nylon series, and the chain tilt angle reduces to 36.6°. These combined results suggest that, even with a relatively low frequency of amide units along the backbone of these molecules, hydrogen bonding is still the dominant element in controlling the behavior, structure, and properties of these polymers. In addition, gels were prepared in concentrated sulfuric acid, and gel‐spun fibers were studied using X‐ray diffraction. The data are interpreted in terms of a modified nylon triclinic α structure that bears a resemblance to the structure of even–even nylons at elevated temperatures. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 40: 2685–2692, 2002     

POLYCAPROLACTAM MODIFIED BY POLYPHENYLQUINOXALINE

Three polycaprolactam samples modified by 0.05—0.50% polyphenylquinoxaline(PPQ)by weight were prepared.Their structure and mechanical properties were characterized by FT-IR, SEM, density, tensile, impact, DTAand visco-elastic method, PPQ induced the formation of "crystal grains" distributed evenly over nylon spherulites in modified samples, which were observed for the first time, and strengthened modified samples. Modified nylons had higher crystallinities, higher T_g, more nearly perfect spherulites than MC nylon itself, and showed typical reinforcing effect on mechanical properties.     

尼龙1212/尼龙6共混体系的非等温结晶行为

用DSC研究了尼龙 12 12 ,尼龙 6及其共混体系的非等温结晶行为 .结果表明 ,加工历史对尼龙的结晶和熔融行为影响很大 .经双螺杆挤出机挤出的尼龙 12 12和尼龙 6 ,由于应力诱导分子链取向 ,其结晶温度都有不同程度的提高 ,且表现出多重熔融现象 .在共混体系中 ,尼龙 12 12分子在共混物的界面上异相成核结晶 ,提高了其结晶温度 ,但酸酐化SEBS的加入抑制了分子链的运动又使其结晶温度降低 .共混体系降低了尼龙12 12的熔融温度 ,并使得其高熔点的熔融峰逐渐消失 ;而尼龙 6的熔融行为基本上没有变化 .     

Synthesis and characterization of novel even-odd nylons based on undecanedioic acid

A series of novel even-odd nylons were synthesized through step-heating melting-polycondensation of undecanedioic acid with various diamines. The synthesized polyamides were characterized comprehensively by means of elements analysis, intrinsic viscosity, Fourier transform infrared (FTIR) spectroscopy, nuclear magnetic resonance (NMR), Raman spectra, thermogravimetry analysis (TGA) and differential scanning analysis (DSC). The obtained products except nylons 4 11 and 2 11 have intrinsic average molecular weights ranging from 1.3 × 10⁴ to 2.5 × 10⁴. Nylons 4 11 and 2 11 have intrinsic average molecular weights of 8400 and 7200, respectively. The melting temperatures of this series of even-odd nylons decrease with declining the concentration of hydrogen bonds. Furthermore, the dynamic mechanical analysis (DMA) was performed for nylons 12 11, 10 11, 8 11 and 6 11. The glass transition temperatures of nylons 12 11, 10 11, 8 11 and 6 11 are in the range of 40.1-45.7 °C.     

Studies on the oxidative degradation of nylons by nitrogen dioxide in supercritical carbon dioxide

Oxidative degradation of nylons was carried out using nitrogen dioxide (NO₂) as the oxidizing agent and supercritical carbon dioxide (scCO₂) as the reaction medium. Seven typical nylons were studied: three ring opening polymerization type nylons (nylon-6, -11 and -12) and four condensation co-polymerization type nylons (nylon-4/6; -6/6; -6/9 and -6/12). All the nylons decomposed in the NO₂/scCO₂ system under relatively mild conditions (140 °C, 1 h, and 10 MPa) and provided aliphatic α, ω-diacids such as succinic, glutaric and adipic acids in good yields. The product distribution of these α, ω-diacids strongly depended on the reaction conditions such as temperature, time and amount of NO₂, but not on the total pressure. Furthermore, the proportions of the products were affected by the type of nylon. A mechanism is proposed and a detailed discussion regarding the degradation of nylon in the NO₂/scCO₂ system is provided.     

含喹噁啉环的化合物改性聚己内酰胺

合成了14种由三种含喹(哑心)啉环的芳香化合物改性的聚己内酰胺(MC尼龙),并对其形态、抗冲击强度、吸水性及熔融行为等进行了表征。聚苯基单醚喹(哑心)啉(PPQ)单模型化合物对MC尼龙结晶部分几乎没有影响。少量(0.005—5.0％)吩嗪的引入使MC尼龙的颜色、形态及性能等发生巨大变化,改性体系被认为是氢键相互作用,PPQ双模型化合物的改性作用介于二者之间。     

含喹噁啉环的化合物改性聚己内酰胺

 合成了14种由三种含喹(哑心)啉环的芳香化合物改性的聚己内酰胺(MC尼龙),并对其形态、抗冲击强度、吸水性及熔融行为等进行了表征。聚苯基单醚喹(哑心)啉(PPQ)单模型化合物对MC尼龙结晶部分几乎没有影响。少量(0.005—5.0％)吩嗪的引入使MC尼龙的颜色、形态及性能等发生巨大变化,改性体系被认为是氢键相互作用,PPQ双模型化合物的改性作用介于二者之间。