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利用ＤＳＣ和偏光显微镜等手段研究了部分成核剂对聚丙烯均聚物（ＰＰ）、低乙烯含量聚丙烯共聚物及聚丙烯／聚乙烯（ＰＰ／ＰＥ）共混物结晶行为的影响，结果表明所用成核剂对ＰＰ和改性ＰＰ具有一定的普适性。聚丙烯共聚物中，由于链结构规整性变差，成核剂的作用显得特别突出，而ＰＰ／ＰＥ共混物中，由于成核剂向ＰＥ相迁移而使其对ＰＰ结晶的成核效率降低。 相似文献
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Due to the mechanical stability of the PP layer, the oriented PP/PE double-layer film with a row-nucleated crystalline structure can be annealed at a higher temperature than the PE monolayer film. In this work, the effects of annealing temperature within the melting range of PE on the crystalline structure and properties of PP/PE double-layer films were studied. When the annealing temperature is between 100 and 130 °C, below the melting point of PE, the crystallinity, the long period, lateral dimension and orientation of the lamellae in the PE layer increase with the annealing temperature due to the melting of thin lamellae and the self-nucleated effect of partially-melted melts during annealing. With the annealing temperature further increasing to 138 °C, near the melting ending point of PE, since the lamellae melt completely and the melt memory becomes weak during annealing, some spherulite structures are formed in the annealed sample, resulting in a decrease of orientation. In contrast, the annealing only causes the appearance of a low-temperature endothermic plateau in the PP layer. The improved size and orientation of lamellar structure in the PE layer increase the pore arrangement and porosity of the stretched PP/PE microporous membrane. This study successfully applies the self-nucleation effect of partially-melted polymer melt into the practical annealing process, which is helpful to guide the production of high-performance PP/PE/PP lithium batteries separator and the annealing process of other multilayer products.
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Chemically synthesized conducting polyaniline (PANI) was investigated as adsorbent for its possible application in the removal of organic dyes, such as methylene blue (MB) and procion red (PR) from their aqueous solution. PANI adsorbent behaves as a charged surface upon post‐synthesis treatment of the polymer with acid and base. The adsorbent thus treated shows a high selectivity for the removal of dyes in the adsorption process. The Langmuir adsorption isotherm was used to represent the experimental adsorption data. The cationic dye, MB can be preferentially removed by the base‐treated PANI while the anionic dye, PR is predominately removed by the acid‐treated one. These observations were further evidenced from the measurements of molar conductance and pH of the dye solutions employed for adsorption. The finding can be explained considering the electrostatic nature of adsorption coupled with the morphology of the PANI surface thus treated. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
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Properties of ethylene-propylene copolymer (EPM) are determined by ethylene/propylene ratio and degree of block and random sequences. EPM was pyrolyzed and the pyrolysis products were analyzed using gas chromatography/mass spectrometry (GC/MS) to examine pyrolysis products formed from the ethylene-propylene heterosequences. Pyrolysis products formed from EPM were compared with those formed from polyethylene (PE) and polypropylene (PP) to determine the pyrolysis products formed from ethylene-propylene heterosequences of EPM. Principal pyrolysis products formed from ethylene-propylene heterosequences were 3-methyl-1-hexene, 4-methyl-1-hexene, 2-methyl-1-hexene, and 2-heptene. Order of the relative intensity of the pyrolysis products was 2-methyl-1-hexene > 4-methyl-1-hexene > 3-methyl-1-hexene > 2-heptene. The relative abundances of the pyrolysis products decreased as the pyrolysis temperature increased. Relative abundances of the specific pyrolysis products formed from ethylene-propylene heterosequences may be used for determination of the relative degree of random sequences of EPM as well as ethylene-propylene-diene terpolymer (EPDM). 相似文献
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采用接枝磺化缩聚法制备了不同相对分子质量碱木质素系水煤浆分散剂(GCL3J系列),研究相对分子质量对水煤浆吸附分散性能的影响。流变学研究结果表明,具有三维空间网络结构的GCL3J分散降黏性能均优于具有线性结构的萘系分散剂。等温吸附和Zeta电位测试结果表明,GCL3J在煤粒表面的吸附特征属于Langmuir型单分子层吸附,随着相对分子质量的增加,其在煤粒上的吸附量逐渐减少,吸附作用力逐渐增强,并逐渐以疏水作用吸附为主。中等相对分子质量的GCL3J-3(Mw为31 500 Da,特性黏度为8.06 mL/g)在煤粒表面吸附后,具有适宜的吸附量和吸附强度,且负电性最高,对水煤浆具有最优的分散降黏作用。 相似文献
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Maria Sokol Ivan Gulyaev Mariia Mollaeva Sergey Kuznetsov Vladimir Zenin Maksim Klimenko Nikita Yabbarov Margarita Chirkina Elena Nikolskaya 《Journal of separation science》2023,46(3):2200731
While histone deacetylase inhibitors, such as vorinostat, demonstrate a significant effect against hematological cancers, their application for solid tumor treatment is limited. However, there is strong evidence that combinatorial administration of vorinostat and genotoxic agents (e.g., doxorubicin) enhances the antitumoral action of both drugs against tumors. We developed a high-performance liquid chromatography method for the simultaneous determination of doxorubicin and vorinostat in polymeric nanoparticles designed to provide the parenteral administration of both drugs and increase their safety profile. We performed separation on Nucleodur C-18 Gravity column with a mixture of 10 mM potassium dihydrogen phosphate buffer pH 3.9:ACN (90:10 v/v) as mobile phase at 240 nm. The method was linear within the concentration range of 4.2–52.0 μg/ml for both drugs with limits of detection and quantification of 3.5 and 10.7 μg/ml for doxorubicin and 2.5 and 7.7 μg/ml for vorinostat, respectively. The method was precise and accurate over the concentration range of analysis. Drug loading was 5.4% for doxorubicin and 0.8% for vorinostat. Degradation of doxorubicin after irradiation was less than 5%, while the amount of vorinostat decreased at 88% under the same conditions. Thus, the validated method could be adopted for routine simultaneous analysis of doxorubicin and vorinostat in polymeric nanoparticles. 相似文献
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PAN Bingcai CHEN Jinlong XIONG Ying SUN Yue ZHANG Quanxing State Key Laboratory of Pollution Control Resources Reuse Department of Environmental Engineering Nanjing University Nanjing China 《Chinese Journal of Reactive Polymers》2002,(1)
1. INTRODUCTION Phenylacetic acid is a common intermediate of pesticide, flavor and medicine. It is generally produced by hydrolysis of benzyl cyanide, but it will destroy the environment and human health seriously due to the toxicity of the raw material… 相似文献
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G. Dlubek D. Bamford A. Rodriguez‐Gonzalez S. Bornemann J. Stejny B. Schade M. A. Alam M. Arnold 《Journal of Polymer Science.Polymer Physics》2002,40(5):434-453
Positron annihilation lifetime spectroscopy (PALS), density, and differential scanning calorimetric (DSC) measurements were used to study systematically the variation of the glass‐transition temperature (Tg) and the size v and number density Nh of local free volumes in n‐alkyl‐branched polypropylenes. The samples were metallocene‐catalyzed propylene copolymers with different α‐olefins (from C4 to C16) and a different α‐olefin content (between 0 and 20 mol %). From the total specific volume and crystallinity the specific volume of the amorphous phase Va was estimated and used to calculate the fractional free (hole) volume h and value of Nh. The variations of Tg, v, Va, h, and Nh were related to the degree (number and length) of branching. Tg decreases and v increases linearly with the number and length of n‐alkyl branches. This behavior was attributed to an increased segmental mobility caused by branching. Both values, Tg and v, follow linear master curves as a function of the degree of branching (DB) if this is defined as the number of all side‐chain carbons with respect to a total of 1000 (main‐chain and side‐chain) carbons. Only propylene/1‐butene copolymers deviated from these relations. A linear relation between v and Tg was also found. The number density of holes was estimated to be Nh = 0.49(±0.07) nm?3 and Nh′ = 0.58(±0.11) × 1021 g?1, respectively. It shows a slight variation with the DB, which is also seen in the behavior of the specific volume Va. This variation was explained by the appearance of sterical hindrances resulting from short‐chain branches that may prevent an efficient packing of the chains. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 40: 434–453, 2002; DOI 10.1002/polb.10108 相似文献
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利用密度泛函理论研究了CO2在Fe3O4（111）表面Fetet1和Feoct2两种终结的吸附行为。在Fetet1终结表面,当覆盖度为1/5 ML时,CO2倾向于线性吸附;而在高覆盖度下,弯曲的CO2与表面O作用形成CO32-结构。在Feoct2终结表面,CO2倾向于弯曲吸附,在1/6 ML和1/3 ML覆盖度时都可以形成CO32-和-COO结构。覆盖度对Fetet1终结的表面影响很弱,但是对Feoct2终结的表面影响很大。从热力学上来说,CO2在Feoct2终结表面的吸附要比Fetet1终结表面更有利。 相似文献
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Nur Shakinah Razali Ahmed Saud Abdulhameed Ali H. Jawad Zeid A. ALOthman Tarek A. Yousef Omar K. Al-Duaij Norah Salem Alsaiari 《Molecules (Basel, Switzerland)》2022,27(20)
In this study, Mango (Mangifera indica) seeds (MS) and peels (MP) seeds mixed fruit wastes were employed as a renewable precursor to synthesize high-surface-area-activated carbon (MSMPAC) by using microwave-induced ZnCl2 activation. Thus, the applicability of MSMPAC was evaluated towards the removal of cationic dye (methylene blue, MB) from an aqueous environment. The key adsorption factors, namely A: MSMPAC dose (0.02–0.1 g), B: pH (4–10), and C: time (5–15 min), were inspected using the desirability function of the Box-Behnken design (BBD). Thus, the adsorption isotherm data were found to correspond well with the Langmuir model with a maximum adsorption capacity of (232.8 mg/g). Moreover, the adsorption kinetics were consistent with both pseudo-first-order and pseudo-second-order models. The spontaneous and endothermic nature of MB adsorption on the MSMPAC surface could be inferred from the negative ∆G° values and positive value of ∆H°, respectively. Various mechanisms namely electrostatic forces, pore filling, π-π stacking, and H-bonding govern MB adsorption by the MSMPAC. This study demonstrates the utility of MS and MP as renewable precursors to produce high-surface area MSMPAC with a potential application towards the removal of cationic organic dyes such as MB. 相似文献
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大孔交联聚(对乙烯基苄基苯基醚)树脂对苯酚的吸附机理 总被引：1，自引：0，他引：1
由氯甲基化聚苯乙烯合成了大孔交联聚(对乙烯基苄基苯基醚)树脂(简称为苯基醚树脂), 测定了其对正己烷和水中苯酚的吸附等温线, 计算了吸附焓. 同时, 比较了聚(对乙烯基苄甲醚)、苯基醚树脂、聚(对乙烯基苄基对硝基苯基醚)和聚(对乙烯基苄基对甲基苯基醚)对正己烷中苯酚的吸附性能以及氯甲基化聚苯乙烯和苯基醚树脂对水中苯酚、2,3,5-三甲基苯酚和对硝基甲苯的吸附性能. 结果表明, 苯基醚树脂是通过氢键吸附正己烷溶液中苯酚的, 而其对水中苯酚的吸附是基于氢键和疏水作用的协同. 相似文献
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通过磨盘碾磨制备了PP/石墨复合粉末 .用FT-IR ,XRD和DSC表征了磨盘剪切力场作用下,PP/石墨体系中 ,聚丙烯结构与性能的变化.结果表明 ,磨盘碾磨使PP有序结构破坏 ,分子链断裂并与石墨的表面官能团之间发生了固相力化学反应 ,导致其结晶度降低 (由57.2%降低到26.4%),晶面间距增大((010)面由0.623nm增加到0.632nnm) ,晶粒尺寸减小 (由12.83nm减小到6.48nm),这些变化 ,在热压成型的非等温过程中部分得到恢复 ,且α-晶的(040)面生长有择优性,其XRD强度大大超过(010)面 ,微晶尺寸更大 .同时发现 ,在PP/石墨复合粉末和复合材料中,α-单斜晶部分地转化为γ-三斜晶 ,在PP/石墨复合材料中,γ-三斜晶占34.8%. 相似文献
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