PREPARATION OF MICROPOROUS ULTRA HIGH MOLECULAR WEIGHT POLYETHYLENE (UHMWPE) BY THERMALLY INDUCED PHASE SEPARATION OF A UHMWPE/LIQUID PARAFFIN MIXTURE

Ultra-high molecular weight polyethylene (UHMWPE) with a microporous structure was prepared via thermally induced phase separation (TIPS).Liquid paraffin (LP) was used as a diluent in the preparation of microporous UHMWPE. Small angle laser light scattering (SALLS) and differential scanning calorimetry (DSC) were used to determine the phase separation temperatures,i.e.the cloud points and the dynamic crystallization temperatures,respectively.It was found that the cloudI points were coincident with the cryst...

Biodegraded Oil and Its High Molecular Weight (C_(35+)) n-alkanes in the Qianmiqiao Region in the Bohai Bay Basin, Northern China

With a production of 208.2 m3/d, heavy oil was produced by drill stem test (DST) from three shallow reservoirs in Sand Group Nos. Ⅰ and Ⅲ of the Neogene Guantao Formation (NgⅠ and NgⅢ) and the Eogene Dongying Formation (Ed) in an exploratory well Ban-14-1 within the Qianmiqiao region, Bohai Bay Basin, northern China. Based on the GC and GC-MS data of the NgⅠ and NgⅢ heavy oil samples, all n-alkanes and most isoprenoid hydrocarbons are lost and the GC baseline appears as an evident 'hump', implying a large quantity of unresolved complex mixture (UCM), which typically revealed a result of heavy biodegradation. However, there still is a complete series of C14-C73 n-alkanes in the high-temperature gas chromatograms (HTGC) of the heavy oil, among which, the abundance of C30- n-alkanes are drastically reduced. The C35-C55 high molecular weight (HMW) n-alkanes are at high abundance and show a normal distribution pattern with major peak at C43 and an obvious odd-carbon-number predominance with CPI37-55 and OEP45-49 values of 1.17 and 1.16-1.20, respectively. According to GC-MS analysis, the heavy oil is characterized by dual source inputs of aquatic microbes and terrestrial higher plants. Various steranes and tricyclic terpanes indicate an algal origin, and hopane-type triterpanes, C24 tetracyclic terpane and drimane series show the bacterial contribution. With the odd-carbon-number preference, HMW n-alkanes provide significant information not only on higher plant source input and immaturity, but also on the strong resistibility to biodegradation.

Biosynthesis of poly-3-hydroxybutyrate with a high molecular weight by methanotroph from methane and methanol

Poly-3-hydroxybutyrate （PHB） can be produced by various species of bacteria. Among the possible carbon sources, both methane and methanol could be a suitable substrate for the production of PHB. Methane is cheap and plentiful not only as natural gas, but also as biogas. Methanol can also maintain methanotrophic activity in some conditions. The methanotrophic strain Methylosinus trichosporium IMV3011 can accumulate PHB with methane and methanol in a brief nonsterile process. Liquid methanol （0.1%） was added to improve the oxidization of methane. The studies were carried out using shake flasks. Cultivation was performed in two stages： a continuous growth phase and a PHB accumulation phase under the conditions short of essential nutrients （ammonium, nitrate, phosphorus, copper, iron （Ⅲ）, magnesium or ethylenediamine tetraacetate （EDTA）） in batch culture. It was found that the most suitable growth time for the cell is 144 h. Then an optimized culture condition for second stage was determined, in which the PHB concentration could be much increased to 0.6 g/L. In order to increase PHB content, citric acid was added as an inhibitor of tricarboxylic acid cycle （TCA）. It was found that citric acid is favorable for the PHB accumulation, and the PHB yield was increased to 40% （w/w） from the initial yield of 12% （w/w） after nutrient deficiency cultivation. The PHB produced is of very high quality with molecular weight up to 1.5 × 10^6Da.

High-Molecular-Weight Glutenin Subunit Composition of Chinese Wheat Germplasm

The objective of the present study was to characterize the high molecular glutenin subunits （HMW-GS） composition and the presence of 1B/1R translocation in newly developed wheat （Triticum aestivum L.） germplasm, which have one or more traits that are useful in wheat improvement. Sodium dodecyl sulphate polyacrylamide-gel electrophoresis （SDS-PAGE） and acid polyacrylamide-gel electrophoresis （A-PAGE） were used to detect HMW-GS composition and the presence of 1B/1R wheat-rye （Secale cereale L.） chromosome translocation in the wheat germplasm. Bread-making quality scores of these lines were determined. A high level of variations in HMW-GS encoded by Glu-1 locus was observed. Sixteen major HMW-GS, with 30 combinations, were detected. The percentage of cultivars with more than two desirable subunits was 38.7%. Thirteen cultivars had bread-making quality scores of 10 in combination with one or two desirable agronomical traits, such as high-yield potential, dwarfing stem, resistance to diseases, and/or tolerance to abiotic stress. Sixty-eight （36.6%） cultivars possessed 1B/1R translocation. The newly developed germplasm with HMW-GS for good quality can be promising resources for improving bread-making quality of wheat.

Molecular Weight Distribution of Dissolved Organic Matter in Lake Hongfeng Determined by High Performance Size Exclusion Chromatography (HPSEC) With On-Line UV-Vis Absorbance and Fluorescence Detection

The molecular weight distribution (MWD) of dissolved organic matter (DOM) in lake waters from Lake Hongfeng was examined using high performance size exclusion chromatography (HPSEC) with UV-vis absorbance and fluorescence detection. The elution curves obtained by absorbance and fluorescence techniques expressed similar patterns, with the exception of diminishing of large fraction and the peaks behind several seconds in fluorescence chromatograms. According to its molecular weight (MW), DOM in water samples is divided into several fractions: large ({>3.5} kDa); medium-large ({3.5}-{2.0} kDa); medium ({2.0}-{1.0} kDa) and small ({<1.0} kDa). The average molecular weight was calculated using the elution curve detected by UV-vis absorbance and fluorescence detection techniques. The results showed that the weight-average molecular weight (Mw) and number-average molecular weight (Mn) calculated by UV-vis absorbance techniques range from 1750 to 2050 Dalton and from 1450 to 1850 Dalton, respectively. And the Mw and Mn obtained by fluorescence detection are lower by 50 to 400 Dalton. As a reference, the molecular weight of Fluka humic acid (FHA) is larger than that of water samples by about 200 Dalton. The average molecular weight of DOM for water samples collected in March and July was compared. The results revealed that the molecular weight is lower for water samples obtained in July than that obtained in March, indicating the ambient environment has an influence on the molecular weight, including photo-degradation and biological activity.

Switching from Sitagliptin to Alogliptin under Treatment with Pioglitazone Increases High Molecular Weight Adiponectin in Type 2 Diabetes: A Prospective Observational Study

Background: There are few clinical trials addressing the difference in pleiotropic effects among dipeptidyl peptidase (DPP)-4 inhibitors. We aimed to identify difference in effects on biochemical markers of inflammation, oxidative stress, and atherosclerosis between two DPP-4 inhibitors in patients with type 2 diabetes. Methods: We prospectively observed twenty subjects with type 2 diabetes before and after a practical medication change from a treatment with pioglitazone and sitagliptin 50 mg to a combination tablet containing the same dose of pioglitazone and alogliptin 25mg, which was actually identical to switching from sitagliptin to alogliptin. After 3 months, changes from baseline in clinical data and various biochemical markers were evaluated. In particular, body mass index (BMI) and hemoglobin A1c (HbA1c) were additionally followed after 12 months for evaluation of chronic outcomes. Results: Among markers, serum levels of high molecular weight (HMW) adiponectin significantly increased from 6.9 ± 3.6 μg/ml to 8.2 ± 4.0 μg/ml (P = 0.0045). Although no clinical data changed after 3 months, significant improvements in HbA1c and BMI were observed after 12 months. Their rates of changes tended to inversely correlate with the increased percentages of serum HMW adiponectin levels during initial 3 months, but they did not reach statistical significance. Conclusions: In spite of pretreatment with pioglitazone, additional increase in serum HMW adiponectin levels was demonstrated after switching from sitagliptin to alogliptin. Given multiple favorable roles of adiponectin in metabolic and cardiovascular states, alogliptin, at least when combined with pioglitazone, would be beneficial in treatment of type 2 diabetes.

双向同性自增强UHMWPE板材的制备

在室温条件下,对超高分子量聚乙烯(UHMWPE)模压板双向辊压,以实现双向自增强。探究了双向均匀提升模压板性能的技术可行性,考察了辊压比对模压板球晶形变的影响以及自增强板材聚集态结构与其力学性能的关联性。结果表明,辊压使原模压板约71.2 nm的球晶细化至39.4 nm的微晶,结晶度从45.2%降至40.2%,部分正交晶系转变为单斜晶系。辊压比达36.6%的自增强板材,两个方向的拉伸强度分别达到了62、60 MPa。

Structure and Properties of Self-reinforced Material Made from Ultra-high Molecular Weight Polyethylene-montmorillonite Nanocomposite

High-strength and high-modulus ultra-high molecular weight polyethylene(UHMWPE), named self-reinforced material, was obtained by the elongation of UHMWPE-montmorillonite nanocomposite at melting temperature. According to the scanning electron microscope(SEM) analysis, a great deal of fibrillar texture formed in the direction of elongation, and the tensile fractured surface was similar to that of highly oriented fiber. The transmission electron microscope(TEM) and selective area electron diffraction(SAED) analyses reveal that the reinforced phase of the self-reinforced material is an extended chain crystal and its size is about 50_200 nm wide and several microns long, and the montmorillonite layers are broken up to pieces in the size from 100 to 10 nm. The broken layers which have a huge surface area interacting strongly with macromolecules reduces the entanglement density of UHMWPE and induces the chain orientation in flow field. It is supposed that the astriction of montmorillonite layers to polyethylene chains is not only end-tethered but also side-tethered. The differential scan calorimetry(DSC) analysis shows that there are two endothermal peaks for the self-reinforced material, of which the peak at a higher temperature(136.4 ℃) is ascribed to the melting of the reinforced phase.

Determination and Temperature Dependence of Plateau Modulus for Polymerization of Propylene to Isotactic Polypropylene with Ultra-high Molecular Weight under Catalysis of Ziegler-Natta Catalyst

The viscoelastic behavior of isotactic polypropylene with ultra-high molecular weight(UHPPH) and broad molecular weight distribution(MWD), produced in the presence of Ziegler-Natta catalyst, was investigated by means of oscillatory rheometry at 180 and 200 ℃, whose loss modulus(G″) plots at 180 and 200 ℃ versus the natural logarithm of angular frequency(ω) present a pronounced maximum at 34.35 and 69.21 rad/s, respectively, and do not show a maximum peak at 0.01-100 rad/s for Ziegler-Natta catalyzing ethylene-propylene random copolymerization(PPR) with a conventional molecular weight and broad MWD. The fact indicates that the high molecular weight is responsible for a maximum peak of G″(ω) vs. lnω curves for UHPPH. This makes it possible to determine the plateau modulus(G 0_N) of UHPPH from a certain experimental temperature G″(ω) curve directly. For UHPPH, the G 0_N determined to be 4.28×10 5 and 3.62×10 5 Pa at 180 and 200 ℃, respectively, decreases with the increase of temperature and is independent of the molecular weight, which directly confirms reputation theoretical prediction that the G 0_N has no relation to the molecular weight.

捻度对渔用UHMWPE裂膜纤维线股拉伸性能与耐磨性能的影响研究

为促进超高分子量聚乙烯裂膜纤维(简称UHMWPE裂膜纤维)在渔用绳网中的应用,以膜裂法制备渔用UHMWPE裂膜纤维为原料,通过加捻制备渔用UHMWPE裂膜纤维线股,在此基础上,考察了加捻对UHMWPE裂膜线股的线密度、直径、拉伸性能和耐磨性能的影响。结果显示:UHMWPE裂膜纤维线股随捻度的增加表现出直径逐渐减小、实际线密度先增大后减小以及捻回角逐渐增加等特征;对于不同线密度规格的UHMWPE裂膜纤维线股,随着捻度的增加,其断裂强力均呈现降低的趋势,且纤维线密度越低,加捻对线股断裂强度的影响越小;1600 D的UHMWPE裂膜纤维线股的磨损次数随捻度的增加而降低,而3200和4800 D线股的磨损次数随捻度的增加呈现先降低后升高的变化趋势,且4800 D的不同捻度的线股之间的磨损次数无显著性差异(P<0.05),显示出纤维线密度越大,加捻对其耐磨性能的影响越小。1600、3200和4800 D的UHMWPE裂膜纤维线股的结节强力随捻度的增大呈现先升高后降低的变化趋势,当预加捻度为120 T·m^(-1)时,3种线密度线股的结节强力达到最大值,分别为204.15、373.5、562.41 N,较未加捻UHMWPE裂膜纤维分别提高了50.14%、37.13%和30.22%。在本实验捻度设置范围内,1600 D裂膜线股的结节强度随捻度的增加而增大,较未加捻裂膜纤维结节强度提高了32.49%。研究表明,无捻或低捻度、低线密度UHMWPE裂膜纤维线股可用于UHMWPE裂膜纤维无结网的制备;无捻或低捻度的高线密度UHMWPE裂膜纤维线股则具有较好的耐磨性能;中高捻度、低线密度UHMWPE裂膜纤维线股可用于UHMWPE裂膜纤维有结网的制备。研究结果可为渔用UHMWPE裂膜纤维绳网材料的加工、开发与应用提供参考。

Composition and Content of High-Molecular-Weight Glutenin Subunits and Their Effects on Wheat Quality

Sedimentation values, flour glutenin macropolymer (GMP) contents, composition and contents of high-molecular-weight (HMW) glutenin subunits (GS) of 233 flour samples were determined. Our data indicated that subunit 1 occurred more frequently at Glu-A1 , subunit pair 7 + 8 at Glu-B1 and 2 + 12 at Glu-D1. The significant relationships between Glu-1 quality score and total HMW glutenin content, sedimentation value and GMP content suggested that the composition of HMW-GS affects wheat quality strongly. Moreover, the total content of HMW-GS was correlated with certain quality parameters more significantly. Relationship between subunit 5 + 10 content and breadmaking quality was better than others, but 2 + 12, 7 + 8, 7 + 9 and 4 + 12 also correlated with certain quality parameters significantly. The contents of total HMW-glutenin, x-type subunits and y-type subunits related with sedimentation value, flour GMP content, and Glu-1 quality score more strongly than that of individual subunit or subunit pair. The flour GMP content, with excellent correlation to sedimentation value, total contents of HMW glutenin, x- and y-type subunits and many other quality parameters, could be an ideal indicator of breadmaking quality at earlier generations for breeding purpose for its simple procedure and small scale.

Pt Complexes with High Molecular Weight Polyvinylmethyldimethylsiloxane Ligands Supported on Diatomite for Liquid-phase Hydrosilylation of 3, 3, 3-Trifluoropropene with Methyldichlorosilane

Pt complexes with high molecular weight polyvinylmethyldimethylsiloxane （HMPVMS） ligands supported on diatomite as a catalyst for the hydrosilylation of 3, 3, 3-trifluoropropene and methyldichlorosilane. Results show that this catalyst displays good thermal stability, high activity and excellent recyclability, and it can be readily fabricated by a simple process.

Manufacturing of Ultra-high Molecular Weight Polyethylene Fiber Reinforced Tape and the Loss of Strength

Due to the low density and excellent mechanical proper-ties,high performance fiber reinforced materials have aconsiderable application in the area of high technologyand dally usage.In this paper,the Ultra-high Molecu-lar Weight Polyethylene(UHMWPE)fiber reinforcedPE tape prepared with the method of powder impregnat-ion was studied.The effect of impregnate length and thetensile force of the yarn on the fiber content as well as on the strength and modulus of the tape were discussed.Calculation shows that the strength and the modulus ofthe ULMWPE fiber can keep about 85％ after it undergothe process.

Preparation of High Molecular Weight Poly(L-lactide-co-caprolactone)(85-15)

Poly（L-lactide-co-caprolactone）（85-15）[P（LLA-CL）（85-15）] was synthesized from high purity L-lactide and e-caprolactone using tin octoate as initiator by ring-opening polymerization, and characterized by infrared spectrum and IH-NMR spectrum. The synthesized P（LLA-CL）（85-15） is a random copolymer. The influences of polymerization temperature, polymerization time, dosage of initiator and polymerization pressure on the weight average molecular weight and the polydispersity index of P（LLA-CL）（85-15） were investigated. The optimum preparation conditions of P（LLA-CL）（85-15） are： the polymerization pressure is less than 0.5 Pa, the polymerization temperature is 130 ~C, the n（M）/n（I） ratio is 8 000/1, and the polymerization time is 36 h. Under the condition, the weight-average molecular weight of prepared P（LLA-CL）（85-15） is 65.6x 104, and molecular weight distribution coefficient is 1.15.

Ultra-High Molecular Weight Polyethylene Tape Applied for Distal Humeral Condyle Fracture around Total Elbow Arthroplasty in Patients with Rheumatoid Arthritis: Report of Two Cases

Managing fractures of distal humerus in patients with rheumatoid arthritis (RA) is technically challenging. Total elbow arthroplasty (TEA) is one of the treatment options for these fractures. While elbow motion is largely regained by TEA, comminuted condyle fragments are often ignored. Although numerous approaches for repair of condylar fragments around TEA are described, any universal fixation strategy for these fractures has not been established. This report describes, for the first time, application of an ultra-high molecular weight polyethylene (UHMWPE) tape for the treatment of distal humerus fracture in 2 patients with rheumatic elbow arthropathy. The post-operative clinical courses were good. Radiographs showed bony union of the condylar fragments without loosening in two cases. Because of its flat configuration, softness, and flexibility, UHMWPE tape is a promising material for stabilizing fracture of the distal humerus associated with TEA.

The influence of adiponectin G276T gene polymorphism on changes in total and high molecular weight adiponectin levels by exercise training

Adiponectin is an adipocyte-secreted hormone and regulates the metabolism of lipid and glucose. We examined the influence of adiponectin G276T gene polymorphism on changes in total or high molecular weight adiponectin levels by exercise training. A randomized parallel-design study (n = 53;40 women and 13 men;age range, 32 - 65 years) was conducted. Participants were randomly assigned to the exercise (n = 26) or control (n = 27) group and received exercise training for 70 min 2 times per week for 12 weeks and exercise advice at the baseline, respectively. Blood sample were obtained before and after the intervention. The primary outcomes were changes in total adiponectin and high molecular weight adiponectin levels. At the baseline, the participants with and without 276G allele did not differ with the total and high molecular weight adiponectin levels in the entire study population. No significant difference in the change in the total and high molecular weight adiponectin levels between the subjects with the G276G genotype and 276T allele carriers were found. This study provides evidence that the G276T polymorphism of the adiponectin gene is not associated with the magnitude of the effect of twice-weekly exercise training on the total and high molecular weight adiponectin levels.

乙烯-丙烯酸共聚物改性环氧树脂/UHMWPE纤维复合材料的制备与性能研究

使用乙烯-丙烯酸共聚物(EAA)与环氧树脂复配作为基体,利用水基乳液浸渍超高分子量聚乙烯(UHMWPE)纤维制备了复合材料,通过在树脂浸润性、树脂耐热性能、复合材料力学性能、界面结合情况以及微观形貌等方面的测试表征,对比了不同EAA含量的基体树脂对UHMWPE纤维复合材料性能的影响。结果表明,EAA与环氧树脂质量比为25∶75的共混体系一方面可发挥EAA组分与UHMWPE纤维间亲和力强的优势,另一方面还能凭借环氧树脂的刚性交联网络保持较高的耐热性能,体系的层间剪切强度达到8.7 MPa,在60℃下弯曲强度保持率接近80%,表现出优异的综合性能。

PREPARATION AND CHARACTERIZATION OF ULTRA-HIGH MOLECULAR WEIGHT POLY(ETHYLENE TEREPHTHALATE)(PET)FIBER

This paper reports the spinning and drawing behavior of Ultra-high Molecular Weight polyethylene Terephthalate) (UHMW-PET) fibers. The as-spun fibers were produced by dry-jet wet spinning of a 15%-17% solution in 50:50(v:v) trifluroroacetic acid and dichloromethane. Both molecular weight and polymer solution concentration have marked effect on the drawability of the as-spun-fibers. The maximum extension drawing ratio (EDRmax) of as-spun fiber increases with increasing molecular weight, whereas optimal concentration to achieve the EDRmax of as-spun fibers decreases with increasing molecular weight. Drawing speed and temperature during the first step have remarkable effect on the drawability of these fiber during the second step. Relatively lower drawing temperature and drawing speed (19 ℃ , 60 mm/min) during the first drawing step was beneficial to mechanical properties of ultimate fibers. At the range of 210 ℃ to 230 ℃, the draw ratio (DR) during the second step increases with increasing temperature.