芳香聚醚酮酮晶体结构及其晶型变化的研究（Ⅰ）

利用Ｘ射线及热分析技术研究了聚醚酮酮（ＰＥＫＫ）的溶剂诱导结晶及从玻璃态结晶和从熔融态结晶的行为。发现ＰＥＫＫ有两种晶型结构（Ⅰ和Ⅱ），晶型Ⅱ的形成与热历史和溶剂诱导有关，其熔点始终低于Ⅰ型１０℃左右。ＰＥＫＫ的低温熔融峰与其分子链极化有关，而与热历史无关，此低温熔融峰热焓占总热焓２％～１０％，其平衡熔点为４０９℃。     

聚醚醚酮酮和含联苯聚醚醚酮酮共聚物的熔融热

根据Ｆｌｏｒｙ热力学统计理论和比容－熔融热作国法，由ＤＳＣ结果得到了不同联苯含量的聚醚醚酮酮－含联苯聚醚醚酮酮（ＰＥＥＫＫ－ＰＥＢＥＫＫ）共聚物的熔融热，两种方法获得的结果吻合。在此基础上给出了ＰＥＥＫＫ－ＰＥＢＥＫＫ共聚物不同联苯含量的熔点计算表达式。结果还表明，随着联苯含量ｎＢ，的变化，明显改变；当ｎＢ＝０．３５时，ＰＥＥＫＫＰＥＢＥＫＫ共聚物的值最小。     

聚醚醚酮酮的结晶熔融行为

用差示扫描量热法（ＤＳＣ）研究不同热历史聚醚醚酮酮（ＰＥＥＫＫ）的结晶熔融行为。在２２５－３００℃等温热处理样品的ＤＳＣ曲线出现了熔融双峰。低温熔融峰峰温（Ｔｍｌ）较低，Ｔｍｌ与热处理温度Ｔｃ有关；高温熔融峰峰温（Ｔｍ２）较高，Ｔｍ２几乎不受Ｔｃ的影响。研究结果认为，在升温过程中存在结晶的熔融－重结晶过程，熔融双峰归因于结构相同而完整程度不同的ＰＥＥＫＫ结晶的熔融行为。还探讨了升温速度对结晶熔融行     

用对称透射二维WAXS强度研究PET取向非晶态结构

用对称透射法，测试聚酯（ＰＥＴ）取向非晶试样的二维广角Ｘ射线散射相干强度Ｉ（Ｋ，α），将不同方位角α上的Ｉ（Ｋ，α）非晶重叠峰曲线进行计算分解，获得分子链间原子散射引起的二个峰为Ａ（Ｋ＝０．１２６），Ｂ（Ｋ＝０．１６９），分子链内原子散射引起五个峰分别为Ｃ（Ｋ＝０．３０４），Ｄ（Ｋ＝０．５５３），Ｅ（Ｋ＝０．３７４），Ｆ（Ｋ＝０．４６５），Ｇ（Ｋ＝０．６０６），Ｋ单位为ｎｍ＾－１，分析了它们的结构     

茂金属间规立构聚丙烯结晶动力学研究

用ＤＳＣ和密度法对茂金属间规立构聚丙烯（ｓＰＰ）样品进行了等温和非等温结晶动力学研究．测得平衡熔点Ｔ０ｍ为１５８℃,平衡熔融热焓ΔＨ０ｍ为３７ｋＪ／ｍｏｌ,侧表面自由能σ＝５２ｅｒｇ／ｃｍ２,折叠链表面自由能σｅ＝６９ｅｒｇ／ｃｍ２,链堆砌功ｑ＝３３７５ｋＪ／ｍｏｌ．对非等温结晶过程研究表明,由熔体结晶的ｓＰＰ具有非均相成核,三维球状生长机理．成核与生长活化能ΔＥ＝７３１ＫＪ／ｍｏｌ     

二苯醚—对苯二甲酰氯—4,4‘—二苯氧基二苯砜三元共聚物的合成与性能

以无水ＡｌＣｌ３／ＣｌＣＨ２ＣＨ２Ｃｌ／ＮＭＰ为催化剂／溶剂体系，通过缩聚反应，由二苯醚，对苯二甲酰氯和４，４－二苯氧基二苯砜合成了聚醚酮酮和聚醚砜醚酮酮共聚物（ＰＥＫＫ／ＰＥＳＥＫＫ）．考察了单体浓度、反应时间对聚合物分子量的影响，并对其进行了ＩＲ、ＤＳＣ、ＷＡＸＤ等分析表征．结果表明，共聚物具有优异的耐热性，随着共聚物中ＰＥＳＥＫＫ单元含量的增加，其玻璃化温度逐渐升高，而熔融温度和结晶度逐渐降低．与聚醚酮酮（ＰＥＫＫ）相比，共聚物的断裂伸长率明显提高，而拉伸强度和拉伸模量却有所下降，但仍具有良好的力学性能．     

聚醚醚酮酮（PEEKK）和含联苯结构聚醚醚酮酮（PEBEKK）共聚物的SAXS研究

应用一维电子密度相关函数方法，对含不同联苯结构的ＰＥＥＫＫ－ＰＥＢＥＫＫ共聚物样品小角Ｘ射线散射（ＳＡＸＳ）去模糊强度分析计算表明：ＰＥＥＫＫ－ＰＥＢＥＫＫ共聚物的聚集态结构明显地依赖于共聚物中联苯含量。当联苯含量ｎｂ＝０．３５时，积分不变量Ｑ，长周期Ｌ，平均结晶片层厚ｄ，电子密度差η_ｃ－η_ａ和结晶度Ｗ_（ｃ，ｘ）值为最小，比表面积Ｏ_ｓ为最大。     

LDPE－g－MALa离聚物的研究

详细地研究了ＬＤＰＥ熔融接枝马来酸镧（ＭＡＬａ）的反应。产物ＬＤＰＥ－ｇ－ＭＡＬａ的ＩＲ表明在波数１５４９ｃｍ－１和１６２８ｃｍ－１处出现了羧酸盐的Ｃ＝０伸缩振动峰，说明ＭＡＬａ已接枝在ＬＤＰＥ上；ＷＡＸＤ衍射结果则表明在２θ＝１７．２０°、１４．２０°处出现了新的衍射峰—离子峰。为了控制熔融接枝过程，考察了各种瓜条件对接枝率的影响。同时，ＤＳＣ的结果表明离聚物中离子微区的存在在结晶过程中可以起到较好的成核作用。     

聚芳醚酮膜的溶剂吸附与诱导结晶行为

研究了聚芳醚酮系列在１，２－二氯乙烷中的吸附，及溶剂与温度诱导结晶行为。得到６０℃时的最大吸附量Ｃ∞及假扩散系数Ｄ为：ＰＥＥＫ，Ｃ∞＝４６％，Ｄ＝３．１０×１０＾－１２ｍ＾２·ｓ＾－１；ＰＥＥＫＫ，Ｃ∞＝５０％，Ｄ＝６．５７×１０＾－１２ｍ＾２·ｓ＾－１；ＰＥＫＫ，Ｃ∞＝５５％，Ｄ＝９．４１×１０＾－１２ｍ＾２·ｓ＾－１。实验表明，吸附及脱附行为均与分子链刚性或羰基含量有关，膜的分子链受溶剂作用而     

REGaSi的合成、结构及Ga-Si成键网络

用电弧熔炼法合成了系列化合物ＲＥＧａＳｉ,采用粉末Ｘ射线衍射方法测定了化合物ＳｍＧａＳｉ的晶体结构,获得其晶体学及结构修正参数为;四方晶系,ＬａＰｔＳｉ类型,（１０９）Ｉ４１ｍｄ,Ｍｒ＝２５０．０,ａ＝０．４１３４（３）ｎｍ,ｃ＝１．４２２（２）ｎｍ,Ｖ＝０．２４３０（５）ｎｍ＾３,Ｚ＝４,Ｄｘ＝６．４６４ｇ．ｃｍ＾－３,Ｆ（０００）＝４２８,Ｔ＝２９６Ｋ。     

Step-scan TMDSC and high rate DSC study of the multiple melting behavior of poly(1,3-propylene terephthalate)

The multiple melting behavior of poly(1,3-propylene terephthalate) (PPT) samples after isothermal crystallization from the melt was studied. The step-scan temperature-modulated differential scanning calorimetry (TMDSC) and high rate DSC were used to investigate this behavior in conjunction with standard DSC, wide-angle X-ray diffraction (WAXD) and polarizing light microscopy (PLM). The effect of PPT average molecular weight on the melting was also examined. In general multiple endotherms after isothermal crystallization of PPT were attributed to a continuous crystal perfection process during the subsequent heating scan via melting-recrystallization-remelting. Multiple melting behavior was more pronounced for the low molecular weight PPT. Step-scan TMDSC showed that extensive recrystallization occurs in PPT samples, especially after rapid isothermal crystallization. In fact two recrystallization exothermic peaks were observed. High rate DSC revealed the initial morphology generated during the isothermal step and showed that the low and middle peaks are associated with melting of primary crystals while the high temperature peak should be attributed to melting of recrystallized material.     

Analysis of Polymorphism and Dual Crystalline Morphologies in Poly(hexamethylene terephthalate)

Summary: The polymorphisms in poly(hexamethylene terephthalate) (PHT), along with their associated melting and spherulite morphologies, were examined by differential scanning calorimetry (DSC), wide‐angle X‐ray diffraction (WAXD), and polarized‐light microscopy (PLM). The morphology and crystal cells were dependent on the temperature of crystallization. When melt‐crystallized at low temperatures (90–135 °C), PHT showed at least five melting peaks and two re‐crystallization peaks upon DSC scanning, and the samples displayed various fractions of both α and β crystals. However, only a single melting peak was obtained in PHT melt‐crystallized at 140 °C or above, which displayed a single type of β crystal. In addition, two different forms of spherulites were identified in melt‐crystallized PHT, with one being a typical Maltese‐cross spherulite containing the α crystal, and the other being a dendrite‐type packed mainly with the β crystal. This study provides timely evidence for a critical interpretation of the relationship between multiple melting and polymorphisms (unit cells and spherulites) in polymers, including semi‐crystalline polyesters.

WAXD diffractograms for PHT melt‐crystallized at 140 °C, revealing a single type of β‐crystal cell.     

Evolution of Morphology and Structure During Crystallization and Melting in Syndiotactic Polypropylene

Polypropylene( PP) has developed into one of the most useful plastic materials.Ithas many attractive properties,among them,a relatively low price.It also possesses awide range of possibilities for chemical modification[1 ,2 ] .The structure and morphologyof PP have a directimpacton the final properties. Therefore,there is growing interestinunderstanding the structure and morphology of stereoregular PP[1～ 6] .　For isotactic PP(i PP) ,extensive structural and morphological studies have be…     

The multiple melting endotherms from poly(butylene terephthalate)

The melting behavior of poly(butylene terephthalate) (PBT) has been investigated, and a simulation has been performed to determine whether the multiple melting endotherms observed during the thermal analysis of PBT can be explained by the simultaneous melting and recrystallization of an initial distribution of crystal melting temperatures that contains only one maximum and two inflection points. Specimens that were cooled at constant rates from the melt showed between one and three melting endotherms upon heating in a differential scanning calorimeter (DSC). The position and breadth of the crystallization exotherms upon cooling from the melt and small-angle x-ray scattering showed that as the cooling rate is increased, the distribution of melting temperatures broadens and shifts to lower temperatures. By combining temperature-dependent recrystallization with an initial distribution of melting temperatures, simulated DSC curves were produced that agreed well with experimental DSC curves. In instances of triple peaked curves, the high temperature peak was due to crystals formed during the scanning process, and the middle and low temperature peaks were due to crystals originally present in the material. Satisfactory agreement between the experimental and simulated curves was found without considering additional crystallization from the amorphous regions during the scanning process.     

聚(丁二酸丁二酯-co-丁二酸丙二酯)的等温结晶行为研究

以1,4-丁二酸、1,4-丁二醇和1,3-丙二醇为原料通过直接熔融缩聚法合成了聚丁二酸丁二酯(PBS),聚丁二酸丙二酯(PPS)和聚(丁二酸丁二酯-co-丁二酸丙二酯)(PBSPS)等脂肪族聚酯.利用1H-NMR,WAXD,DSC和POM等研究了聚酯的结晶结构和结晶动力学过程等结晶行为.PBSPS的结晶晶型与PBS一致,说明只有丁二酸丁二酯(BS)单元结晶而丁二酸丙二酯(PS)单元处于无定形区.聚酯等温结晶后,在升温熔融过程中出现了多重熔融峰.分析表明多重熔融峰主要来自于聚酯升温过程中的熔融-重结晶行为.利用Avrami方程分析了聚酯的等温结晶动力学,Avrami指数n为2.2~2.8,说明聚酯等温结晶时主要以异相成核的三维生长方式进行;随着PS单元的增多,聚酯的表观结晶活化能升高,也就是说BS单元的结晶变得困难.POM观察到聚酯等温结晶时都出现了环带球晶现象,球晶形态会随着结晶温度和化学结构差异而改变.     

磺化间规聚苯乙烯的表征

间规聚苯乙烯(sPS)是一种新型结晶性工程塑料,熔点达270℃,具有结晶速度快、耐热性好、耐化学腐蚀性优良等特点,可广泛用于汽车、电子、机械等行业,极具开发意义,但是由于sPS脆性大,抗冲击性差,故通过化学改性在sPS的苯环上引入极性基团,用于制成共混合金与复合材料,是提高材料韧性,开拓sPS用途的重要途径。     

Multiple melting behavior in isothermally crystallized poly(trimethylene terephthalate)

Melting behavior of poly(trimethylene terephthalate) (PTT) after isothermal crystallization from the melt state was studied using differential scanning calorimetry (DSC) and wide-angle X-ray diffraction (WAXD) techniques. The subsequent melting thermograms for PTT isothermally crystallized within the temperature range of 182-215 °C exhibited triple (for crystallization temperatures lower than ≈192 °C), double (for crystallization temperatures greater than ≈192 °C but lower than ≈210 °C), or single (for crystallization temperatures greater than ≈210 °C) endothermic melting phenomenon. These peaks were denoted peaks I, II, and III for low-, middle-, and high-temperature melting endotherms, respectively. For the triple melting phenomenon, it was postulated that the occurrence of peak I was a result of the melting of the primary crystallites, peak II was a result of the melting of recrystallized crystallites, and peak III was a result of the melting of the recrystallized crystallites of different stabilities. In addition, determination of the equilibrium melting temperature T_m⁰ for this PTT resin according to the linear and non-linear Hoffmann-Weeks extrapolation provided values of 243.6 and 277.6 °C, respectively.     

Thermal and X‐ray analysis of polymorphic crystals,melting, and crystalline transformation in poly(butylene adipate)

Polymorphic crystals and complex multiple melting behavior in an aliphatic biodegradable polyester, poly(butylene adipate) (PBA), were thoroughly examined by wide‐angle X‐ray diffraction (WAXD) and differential scanning calorimetry (DSC). Further clarification on mechanisms of multiple melting peaks related to polymorphic crystal forms in PBA was attempted. More stable α‐form crystal is normally favored for crystallization from melt at higher temperatures (31–35 °C), or upon slow cooling from the melt; while the β‐form is the favored species for crystallization at low temperatures (25–28 °C). We further proved that PBA crystallization could also result in all α‐form even at low temperatures (25–28 °C) if it crystallized with the presence of prior α‐form nuclei. PBA packed with both crystal forms could display as many as four melting peaks (P1 ? P4, in ascending temperature order). However, PBA initially containing only the α‐crystal exhibited dual melting peaks of P1 and P3, which are attributed to dual lamellar distributions of the α‐crystal. By contrast, PBA initially containing only the β‐crystal could also exhibit dual melting peaks (P2 and P4) upon scanning. While P2 is clearly associated with melting of the initial β‐crystal, the fourth melting peak (P4), appearing rather broad, was determined to be associated with superimposed thermal events of crystal transformation from β‐ to α‐crystal and final re‐melting of the new re‐organized α‐crystal. Crystal transformation from one to the other or vice versa, lamellae thickening, annealing at molten state, and influence on crystal polymorphism in PBA were analyzed. Relationships and mechanisms of dual peaks for isolate α‐ or β‐crystals in PBA are discussed. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 1662–1672, 2005     

偏氟乙烯/三氟氯乙烯无规共聚物的结晶

用示差扫描量热法(DSC)、广角X射线衍射(WAXD)和傅里叶红外光谱(FTIR)研究了偏氟乙烯/三氟氯乙烯单体摩尔比为1:4的无规共聚物的结晶与晶体结构.结果表明,该无规共聚物属于半结晶型聚合物.在333～353K温度范围内退火,片晶逐渐完善、增厚,熔点和结晶度均随着退火时间的延长而升高.于353K退火时,由DSC结果计算得到片晶厚度约4.68nm.在333K退火时得到共聚物的最大结晶度约为14%.WAXD测试结果表明,沿晶粒(101)晶面的面间距为0.55nm,垂直于(101)衍射晶面方向上的晶粒平均尺寸为5.86nm.     

New insight into melting and crystallization behavior in semicrystalline poly(ethylene terephthalate)

After isothermal crystallization, poly(ethylene terephthalate) (PET) showed double endothermic behavior in the differential scanning calorimetry (DSC) heating scan. During the heating scans of semicrystalline PET, a metastable melt which comes from melting thinner lamellar crystal populations formed between the low and the upper endothermic temperatures. The metastable melt can recrystallize immediately just above the low melting temperature and form thicker lamellae than the original ones. The thickness and perfection depends on the crystallization time and crystallization temperature. The crystallization kinetics of this metastable melt can be determined by means of DSC. The kinetics analysis showed that the isothermal crystallization of the metastable PET melt proceeds with an Avrami exponent of n = 1.0 ∼ 1.2, probably reflecting one‐dimensional or irregular line growth of the crystal occurring between the existing main lamellae with heterogeneous nucleation. This is in agreement with the hypothesis that the melting peaks are associated with two distinct crystal populations with different thicknesses. © 2000 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 38: 53–60, 2000