聚酯分子量分级参数与高速纺可纺性的研究

建立了高聚物沉淀分级方法,并对切片进行不同分子量分级后样品的统计分析,提出一种较为简明的又能表征分子量分布的新参量——分级参数 R,通过对国内外各种典型切片 R 值的测定.发现 R 值与高速纺可纺性有着密切的关系,切片 R 值高,可纺性较好;R 值低,可纺性差.R 值与聚酯切片制造过程中的工艺和聚合路线有关,通过 R 值可以预测切片对纺丝成形及后加工的影响.     

水泥中铁铝快速流动分光光度法测定

将７２１型分光光度计与ＭＩＡ－Ｉ型离子计联用，用流动分光光度法测定水泥样品中铁、铝，并采取非线性拟合处理有关数据。本法简便、快速，尤其适合于批量大、常量铁、铝的样品分析。     

PP／LDPE共混物熔体流动特性的研究

将两种熔融流动指数（ＭＦＩ）相差大的聚丙烯（ＰＰ）分别与一低密度聚乙烯（ＬＤＰＥ）进行共混，用熔体流动速率仪测定其流动特性。发现ＭＦＩ值高的ＰＰ，当共混比ＰＰ／ＬＤＰＥ为５０／５０时，其熔体流动速率（ＭＦＲ）为最大，本文对此作了初步的分析和讨论。     

PC／PP／MPP合金体系的力学性能与相态结构

本文介绍以马来酸酐接枝ＰＰ（ＭＰＰ）为相容剂，通过熔融共混的方法制备ＰＣ／ＰＰ合金体系，并研究了配方、力学性能和相态结构之间的关系。由力学性能测试和扫描电镜观察的结果表明，在ＰＣ含量（质量分数，下同）小于５５％时，不含ＭＰＰ样品的冲击强度高于含质量分数（下同）为１０％ＭＰＰ样品的冲击强度；大于５５％时，含１０％ＭＰＰ样品的冲击强度高于同等ＰＣ含量的不含ＭＰＰ样品的冲击强度，其峰值出现在ＰＣ含量为８０％～９０％处。体系拉伸和弯曲强度随ＰＣ含量的变化规律相似，在ＰＣ含量小于５５％时，不含ＭＰＰ样品的拉伸和弯曲强度曲线均出现正峰，而含１０％ＭＰＰ样品出现负峰；当ＰＣ含量大于５５％时，二强度随ＰＣ含量的增加几乎线性地增加，并且含与不含ＭＰＰ样品的变化曲线接近重合。由上述力学性能的变化情况可知，ＭＰＰ对合金的相态结构和力学性能有显著的影响，并随连续相的改变而不同     

盐酸甲基安非他命的分析

首次应用核磁共振（ＮＭＲ）、红外吸收光谱（ＩＲ）、紫外吸收光谱（ＵＶ）、气相色谱－质谱（ＧＣ－ＭＳ）、Ｘ射线衍射（ＸＲＤ）以及熔点等法，对盐酸甲基安非他命进行了综合分析，其中Ｘ射线衍射数据与ＪＣＰＤＳ（粉末衍射标准联合委员会）卡片数据有偏差。为此，根据Ｘ 射线粉末衍射峰的Ｉ／Ｉ０ 值，建立了用于分析盐酸甲基安非他命的数据库，并对于分析要求不同的样品提供了一些经验和方法。     

冷却吹风装置对涤纶短纤维纺丝稳定性的影响

主要叙述在ＥＭＳ－ＩＮＶＥＮＴＡ短纤生产线上，采用日本ＦＵＪＩＢＯＮ纸质过滤筒及被我们改型的纸质过滤筒替代烧结金属过滤筒，生产１．０ｄｔｅｘ到１．５６ｄｔｅｘ半消光高强棉型短纤维原丝。从生产实验得知纺丝冷却条件中冷却风速及其分布是影响可纺性及原丝特性，特别是后牵伸性的关键，并讨论了成功使用ＦＵＪＩＢＯＮ过滤筒的方向。     

聚苯乙烯生产中产品MI值的调控方法

以齐鲁４０ｋｔ／ａ聚苯乙烯生产装置为例，对连续本体法的ＧＰＰＳ产品ＭＩ值调控方法进行了分析和探讨，并总结出相应的定性规律和定量关系图，对产品ＭＩ值的调整和控制以及新产品开发提供了切实可行的方法和措施。     

HTCA—丙酮溶液流变行为与可纺性关系的研究

用气压式毛细管流变仪研究了高温法二醋酸纤维素（ＨＴＣＡ）一丙酮纺丝溶液的非牛顿指数ｎ，结构粘度指数Δη和粘液活化能ΔＥη与可纺性的关系。结果表明，ｎ值的增大和Δη的减小有利于改善ＨＴＣＡ－丙酮溶液的可纺性，但难以作为可纺与不可纺的判据。而Δη能较好地表征ＨＴＣＡ－丙酮溶液的可纺性，ΔＥη值越高，流动性和可纺性越差，实验表明ΔＥη高于８０ＫＪ／ｍｏｌ时，其溶液不可纺。在ＨＴＣＡ－丙酮溶液中加入１０￣     

异氰脲酸酯改性MDI及聚氨酯弹性体合成研究

在催化剂作用下，ＭＤＩ自聚生成环状异氰脲酸酯，用此改性ＭＤＩ合成了聚氨酯弹性体。试验结果表明，ＭＤＩ在ＤＭＰ－３０催化作用下的自聚产物主要为三聚体异氰脲酸酯，ＤＭＰ－３０浓度为０．８％时，改性ＭＤＩ－的ＮＣＯ基含量约为ＭＤＩ中含量的５０％；温度对改性程度的影响不明显，在５０℃时改性程度最高；以改性ＭＤＩ合成的弹性体，其热稳定性和力学性能随改性程度的增加而提高。     

西洋参细胞液体培养人参皂甙的动力学研究

重点研究了西洋参细胞在改良 ＭＳ培养液中代谢生长状况（ＭＳ培养基加 ＫＴ０． ２ ｍｇ／Ｌ，ＩＢＡ５ｍｇ／Ｌ，ＭｇＳＯ４９２·５ｍｇ／Ｌ），对其发酵曲线及细胞生长作了检测，并对细胞 生长动力学作了研究，结果表明细胞生长动力学基本符合Ｍｏｎｏｄ比生长速度式，μｍａｘ＝ ０．１６１３ｄ－１，Ｋｓ＝４７．５９ｇ／Ｌ。     

Preparation of poly(divinylbenzene) microspheres with controllable pore structure using poly(propylene)/toluene as coporogen

Poly(divinylbenzene) (poly(DVB)) microspheres with controllable pore structure were synthesized by suspension polymerization in the presence of toluene and low‐molecular weight poly(propylene) (PP) as coporogen. The weight fraction of PP in toluene varied from 0 to 20 wt %, and the feed ratio of coporogen and DVB was kept at 1/1 (vol/vol). Effects of PP weight fraction in coporogen on the specific surface area, the average pore size, the pore size distribution and the total pore volume of final microspheres were examined. As expected, poly(DVB) microspheres prepared with toluene as sole porogen had a high specific surface area (558 m²/g). Using mixtures of toluene and PP as coporogen, it was found that the specific surface area shifted higher values when low levels of PP (2.0–6.0 wt %) in toluene were used as coporogen. However, further increase of PP weight fraction in toluene resulted in progressive decline of the specific surface area. Hg intrusion/extrusion curves and N₂ sorption isotherms implied caged pore structure with some small entrances. Furthermore, most of pore connectivity limitations may be eliminated when the weight fraction of PP in toluene exceeded 10.0 wt %. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

由聚丙烯熔体的流变行为测定其分子量分布

研究了Ｚ３０Ｓ等４种聚丙烯（ＰＰ）切片的流变行为，分别用毛细管流变仪和平板流变仪进行稳态和动态流变特性的测试，测得流变曲线、动态模量及复数粘度。讨论了温度、剪切速率、角频率、分子量（ＭＷ）和分子量分布（ＭＷＤ）对流变行为的影响。研究表明，从稳态和动态测得的流变曲线求得的４种ＰＰ切片的分子量及其分布指数是同落球粘度法与熔融指数法相结合求得的分子量分布指数相吻合的。     

Natural rubber–isotactic polypropylene thermoplastic blends

Thermoplastic elastomers, prepared by melt blending of natural rubber (NR) and isotactic polypropylene (PP) through a dynamic vulcanization technique, were developed during the later 1970s. However, they have certain drawbacks due to thermal degradation and higher molecular weight of NR. In the study reported here, NR was masticated to different levels prior its addition to isotactic polypropylene to improve the flow properties and to reduce the incompatibility resulting from molecular weight mismatch of NR/PP thermoplastic blends. Mixing energy curves of uncrosslinked blends and those of dynamically vulcanized blends crosslinked using different cure systems were compared. The mixing energy curves of blends containing NR of different molecular weight (M _n) and two grades of PP (injection and film grades) were also compared. Technological and processing properties of the dynamically vulcanized (sulphur and peroxide cure systems) and unvulcanized blends were compared with those of the samples containing unmasticated NR. The results indicated that a number average molecular weight in the range 4 × 10⁵ for NR increased the procoessability without significantly affecting the technological properties of NR/PP thermoplastic blends. Among the three cure systems studied Luperox 101 and dicumyl peroxide gave better technological properties than the sulphur‐cured samples. Two antioxidants, viz. quinoline (TDQ) and imidazole (MBI) type, were tried in NR/PP blends. It was found that TDQ imparts better aging resistance compared to MBI. The improvement in processability due to the reduction in molecular weight of natural rubber by mastication is more noticeable in the case of peroxide vulcanized blends compared to sulphur vulcanized samples. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 2063–2068, 2004     

Preparation and characterization of long chain branched polypropylene mediated by different heteroaromatic ring derivatives

Three different heteroaromatic ring derivatives (coagents) were used to adjust the melt radical reaction of polypropylene (PP). From the results of high temperature ¹H NMR and high-temperature size-exclusion chromatography (HT-SEC), all the coagents could quickly convert the tertiary PP macroradicals into resonance stabilized macroradicals and effectively restrain the β-scission of PP macroradicals. Long chain branched structures, without significant bimodal distribution of molecular weight, could be introduced into coagents-functionalized PP samples. Effect of chemical structures of heteroaromatic rings and electron-attracting groups on the molecular structures and melt properties of modified PP samples was studied. The possible reactions of coagents-functionalized PP samples in different theoretical molar ratio of coagent to alkoxy radical were also proposed according to the results of ¹H NMR, torque curves, rheological measurements and HT-SEC coupled with laser light scattering detector.     

Blends of thermoplastic polyurethane and polypropylene. I. Mechanical and phase behavior

Pure thermoplastic polyurethane (TPU), polypropylene (PP), and TPU/PP blends with different weight ratios prepared in a twin‐screw extruder were investigated by dynamic mechanical analysis (DMA), the universal tester for mechanical investigation, and by wide‐angle X‐ray diffraction (WAXD). The addition of PP above 20 wt % to the TPU stepwise changed the ductility and Young's modulus, i.e., apparently a kind of ductile → brittle transition occurred between TPU/PP 80/20 and TPU/PP 60/40 blends. This fact and the result of analysis of WAXD curves indicated matrix → dispersed phase inversion in this concentration region. TPU melt enabled easier migration of the PP chains and prolonged crystallization of PP matrix during solidification process affecting thus crystallite size, orientation, and crystallinity. In accordance to this fact, DMA results indicated partial miscibility of PP with polyurethane in the TPU/PP blends due to the lack of interfacial interaction and adhesion between the nonpolar crystalline PP and polar TPU phases. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104, 3980–3985, 2007     

Rheological properties and morphological evolutions of polypropylene/ethylene‐butene copolymer blends

This work aims at studying the extensional rheological behavior of polypropylene (PP), ethylene‐butene copolymer (PEB) and their blends in the melt. The weight fraction of the PEB in the blend is 20 and 40%, respectively. Dynamic mechanical analysis shows that these two blends exhibit two tanδ peaks corresponding to the glass transitions of the PP and PEB, respectively. Differential scanning calorimeter results indicate that the presence of the PEB does not alter the melting and crystallization temperatures of the PP. Master curves at 170°C are constructed for the storage and loss modulus as well as complex viscosity. The extensional behavior of the PP, PEB, and their two blends is studied. The PEB enhances the strain hardening of the PP. Changes in the blend morphology during the extensional analysis are also studied. POLYM. ENG. SCI., 2012. © 2012 Society of Plastics Engineers     

Structural modifications induced by recycling of polypropylene

The effect of numerous reprocessing cycles on transport properties of isotactic polypropylene (iPP) films was studied and related to the change of molecular weight and molecular weight distribution occurring during the recycling. Sorption curves of dichloromethane vapor in different samples of iPP were analyzed at 25°C to investigate the effect of structure modifications on the sorption mode. Moreover, gas permeability measurements were performed to evaluate the influence of reprocessing on the gas transport properties. The results obtained were attributed to modifications in the molecular structure of the polymer, evidenced from gel permeation chromatography (GPC), and to a different morphology of the films, as results from X-ray diffractograms and dynamic-mechanical thermal analysis (DMTA).     

Applications of rheological torque–time curves to the study of thermooxidative degradation of polypropylene powder

The torque–time curves of polypropylene (PP) powder treated under various thermooxidative degradation conditions were obtained through processing in the mixing chamber of a rheometer. Meanwhile, the Fourier transform infrared (FTIR) spectra of the corresponding samples were determined, and the quantitative analysis of the carbonyl indices of the FTIR spectra of the samples of the PP powder was carried out to provide evidence for the rheological characterization. PP granules, to which an antideteriorant was added before they were commercially supplied so good antidegradation could be achieved, was investigated for the sake of contrast. The analysis of the experimental results showed that the height of the torque–time curve of the PP powder and the corresponding value of the equilibrium torque could be used to characterize or evaluate the variations of the thermooxidative degradation of the PP powder. Under the same processing conditions, the heights of the torque–time curves of the PP powder and the corresponding values of the equilibrium torque decreased with the enhancement of the thermooxidative degradation treatment before mixing; on the contrary, the heights and areas of the characteristic bands of the carbonyl groups in the FTIR spectra of the PP powder and the corresponding values of the carbonyl index increased. The quantitative analysis of the FTIR spectra provided evidence for the conclusion that the heights of the torque–time curves of the PP powder and the corresponding values of the equilibrium torque could be used to characterize or evaluate the thermooxidative degradation of the PP powder. If the treatment under thermooxidative degradation conditions weakened or the degradation of the PP powder just began (i.e., in the viscosity range for processability), the evaluation method using the heights of the torque–time curves of the PP powder or the corresponding values of the equilibrium torque could provide more sensitivity than the method using the values of the carbonyl index. Consequently, the method using the heights of the torque–time curves to evaluate the thermooxidative degradation of the PP powder had its advantages. The application of the torque–time curves could be used to evaluate not only the variation of the thermooxidative degradation of the PP powder treated under aging conditions before mixing but also the variation of the degradation, including the mechanochemical degradation, of the PP powder during the period of mixing. The dependence of the variation of the degradation of the polymer on the processing time during mixing could be evaluated by the study of the variation of the torque–time curves. It can be concluded that the application of torque–time curves to the evaluation of degradation of PP powder has the advantages of being convenient, real‐time, in situ, online, and production‐oriented. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007     

Shear flow behavior and oil distribution between phases in thermoplastic vulcanizates

The high rate shear flow behavior and the morphology of five different oil‐extended polypropylene (PP)/ethylene‐propylene‐diene monomer (EPDM) thermoplastic vulcanizate blends were investigated with the melt flow rate (MFR) of the PP varying from 0.7 to 20. The ratio of rubber to PP is 70 : 30 in three of the thermoplastic vulcanizates (TPVs) and 50 : 50 in the other two TPVs. The distribution of the high‐temperature oil between the PP melt and the rubber is a key parameter because this will affect the viscosity of the PP/oil medium. The object of this study was to estimate the matrix composition in each of the TPVs at processing temperatures and to compare the shear viscosity of the effective matrix with that of the TPV. To this end, several PP/oil mixtures were prepared and their viscosity curves were correlated with the neat PP melt viscosity curves by means of shift factors varying with oil concentration. The oil distribution between the PP and rubber phases was estimated from TEM micrographs of the TPV blends. The results show that the PPs are mixed with oil to different proportions in the different TPVs and the viscosity curves of these mixtures exhibit the same trends in magnitude as the corresponding TPV viscosity curves. Hence, the shear flow of TPVs can be understood more readily in terms of the effective PP/oil medium flow behavior than in terms of the neat PP melt flow. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 113–121, 2004     

LDPE/PP blends modified by peroxide and radiation induced reactions

LDPE/PP polyblends, modified through either peroxide initiated reactions or irradiation, were characterized in terms of rheological and mechanical properties and microstructure. In the presence of peroxide, or through irradiation LDPE crosslinks, PP degrades. Data were obtained at two peroxide concentration levels (0.1 and 1% by weight) and two radiation doses (30 and 100 kGy). The results show that in peroxide modification, the degradation of PP prevails over the crosslinking of LDPE. However, the effect of irradiation of LDPE (crosslinking) is predominant over that of PP (degradation). The irradiation process tends to yield improved mechanical properties vs. peroxide modification for the PP-rich blends. In addition, the melt viscosity and elasticity of the irradiated PP-rich blends are higher than those of the peroxide-reacted blends at a given level of PP content and frequencies between 10 and 100 rad/s. Attempts were made to relate the shape of the rheological curves and the mechanical properties of the blends to the observed changes in their microstructure. © 1994 John Wiley & Sons, Inc.