共查询到20条相似文献,搜索用时 171 毫秒
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采用摩尔比为3:1的多苯基多次甲基多异氰酸酯(PAPI)与聚丙二醇(PPG)合成了活性端基聚氨酯(PU)预聚体,并与自制端羟基不饱和聚酯树脂共混改性,制得改性不饱和聚酯树脂(UPR).研究了不同相对分子质量的PPG对改性UPR粘度的影响;研究了PPG相对分子质量对改性UPR力学性能的影响;利用SEM对改性UPR冲击断面... 相似文献
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采用在双螺杆中熔融共混,以不同相对分子质量聚乙二醇(PEG)作为增塑剂,对聚乳酸(PLA)进行增塑改性,并把改性后的PLA进行熔融纺丝。用扫描电子显微镜(SEM)、熔体流动速率仪(MFR)、单纤维电子强力仪(EYST)和差示扫描量热仪(DSC)对改性PLA纤维进行表征。讨论了不同相对分子质量的PEG对PLA纤维性能的影响,发现随着PEG含量的增加,改性PLA的流动性增加。当PEG质量分数≤8%时,随着PEG含量的增加,改性PLA纤维强度增加,断裂伸长率增加,玻璃化转变温度(Tg)和熔点(Tm)下降。PLA与PEG组分间表现出较好的相容性。PEG200改性的PLA纤维综合效果最好。 相似文献
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聚丙烯/聚丁烯热塑性弹性体共混物力学性能的研究 总被引:11,自引:0,他引:11
采用不同相对分子质量的聚丁烯热塑性弹性体,对聚丙烯(PP)进行共混改性,并研究了共混物的力学性能和热性能.结果表明:不同相对分子质量的聚丁烯热塑性弹性体对PP均具有较好的增韧改性效果,随着共混物中弹性体含量的增加,共混物冲击强度和断裂伸长率均明显增大,而拉伸强度、硬度和耐热温度有一定的下降;在0~20份范围内,当共混物中弹性体含量相同时,相对分子质量较大的聚丁烯热塑性弹性体对PP的改性效果更好,其共混物的拉伸强度、刚性、韧性及耐热性均较高。 相似文献
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选用相对分子质量分别为10 000和20 000的聚乙二醇(PEG 10000,PEG 20000)与氧化锌(ZnO)、马来酸酐(MAH)混合,再与聚丙烯(PP)共混,制备复合抗静电剂(PEG-ZnO-PP),然后将其与PP共混纺丝,制得共混纤维。研究了PEG-ZnO-PP复合抗静电剂的流动性和热性能,考察了共混纤维的力学性能和抗静电性。结果表明:复合抗静电剂的流动性和热性能因PEG的相对分子质量不同而有所不同,含PEG 10000的复合抗静电剂的流动性能较好,且其熔融热焓、熔融结晶温度、结晶放热高于含PEG 20000的复合抗静电剂。共混纤维力学性能和静电半衰期随复合抗静电剂含量的增加而减小,含PEG 20000的共混纤维抗静电效果更好。 相似文献
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《化学推进剂与高分子材料》2016,(1):64-68
以聚乙二醇(PEG)、聚丙二醇(PPG)、二苯基甲烷二异氰酸酯(MDI)为主要原料,1,4–丁二醇(BDO)为扩链剂,合成出遇水膨胀聚氨酯弹性体。研究了不同相对分子质量的PEG、多元醇配比、预聚体w(NCO)以及异氰酸酯指数(R值)对聚氨酯弹性体性能的影响。结果表明:PEG相对分子质量为1 000,m(PPG1000):m(PEG1000)=20:80,预聚体w(NCO)控制为8%~9%,R值为1.06时,制备的膨胀型聚氨酯止水材料综合性能最好。 相似文献
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聚氨酯交联改性聚丙烯酸酯压敏胶的研究 总被引:3,自引:2,他引:1
采用溶液自由基共聚法合成了含有羟基的(甲基)丙烯酸酯共聚物(PA),采用预聚法合成了端-NCO基聚氨酯(PU)预聚体,然后将PA和PU预聚体混合均匀后制备PUA压敏胶。考察了n(-NCO)∶n(-OH)比例、不同相对分子质量(Mn)的聚丙二醇(PPG)和不同类型的聚醚合成的PU预聚体对PUA压敏胶性能的影响。实验结果表明,改性PUA压敏胶的剥离强度随着PU预聚体用量的增加而逐渐降低,最大降幅为8N/30mm左右,但残胶现象可消除;当n(-NCO)∶n(-OH)=3∶2、m(PA)∶m(PU)=10∶1且PPG的Mn为400时,所制取的PUA压敏胶的持粘性较未改性PA压敏胶提高了267%,但初粘性则有所降低;对Mn均为400的聚乙二醇(PEG)和PPG而言,由PEG400合成的PUA压敏胶比由PPG400合成的PUA压敏胶改性效果更好。 相似文献
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综述了近年来聚乙二醇(PEG)共混改性体系的研究进展以及应用情况,对其发展前景进行了展望。PEG与高分子材料混容性好,是应用很广的共混改性材料。PEG共混材料大多采用溶液共混法、熔融共混法和化学交联法制备。采用PEG共混改性其他材料一方面可改善脆性,提高抗冲击性能,另一方面也可提高材料的亲水性和水溶性。 相似文献
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A series of shape memory biodegradable blends from poly(lactic acid) (PLA) and poly(ethylene glycol) (PEG) were prepared by solution casting method. Ethyl cellosolve-blocked polyisocyanate (EC-bp) was synthesized and used as a cross-linker to obtain cross-linked PLA/PEG blends. The chemical structure of the prepared composite was confirmed by Fourier transform infrared spectra. Thermomechanical, thermal and shape memory properties of the blends were investigated and compared by dynamic mechanical analysis, thermogravimetric analysis and shape memory testing. The results showed that EC-bp cross-linked PLA/PEG blends had better thermal and thermomechanical properties than non-cross-linked blends and displayed good shape memory effects in both shape fixity rate and shape recovery rate. Moreover, the effect of EC-bp addition on the rate of biodegradable degradation in a phosphate buffer solution (pH 7.4) was studied at 37?°C. The prepared cross-linked PLA/PEG blends demonstrated better degradation resistance compared to the non-cross-linked blends. 相似文献
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Plasticization of semicrystalline poly(l-lactide) (PLA) with a new plasticizer - poly(propylene glycol) (PPG) is described. PLA was plasticized with PPG with nominal Mw of 425 g/mol (PPG4) and 1000 g/mol (PPG1) and crystallized. The plasticization decreased Tg, which was reflected in a lower yield stress and improved elongation at break. The crystallization in the blends was accompanied by a phase separation facilitated by an increase of plasticizer concentration in the amorphous phase and by annealing of blends at crystallization temperature. The ultimate properties of the blends with high plasticizer contents correlated with the acceleration of spherulite growth rate that reflected accumulation of plasticizer in front of growing spherulites causing weakness of interspherulitic boundaries. In PLA/PPG1 blends the phase separation was the most intense leading to the formation of PPG1 droplets, which facilitated plastic deformation of the blends that enabled to achieve the elongation at break of about 90-100% for 10 and 12.5 wt% PPG1 content in spite of relatively high Tg of PLA rich phase of the respective blends, 46.1-47.6 °C. Poly(ethylene glycol) (PEG), long known as a plasticizer for PLA, with nominal Mw of 600 g/mol, was also used to plasticize PLA for comparison. 相似文献
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Pressure-volume-temperature properties were measured for polymer solutions of poly(propylene glycol) (PPG)+anisole, polymer blends of PPG+poly(ethylene glycol methyl ether) (PEGME), and the blends of PPG+PEGME and poly(ethylene glycol) (PEG)+PPG with anisole at temperatures from 298.15 to 348.15 K and pressures up to 50 MPa. The Tait equation represents accurately the pressure effect on the liquid densities over the entire pressure range. The excess volumes change from positive to negative as increasing the mole fraction of PPG in the binary systems of PPG+anisole and PPG+PEGME. The volumetric data of the related binary systems were correlated with the Flory-Orwoll-Vrij and the Schotte equations of state to determine the binary parameters. By using these determined binary parameters, both equations predicted the specific volumes of the polymer blends with anisole to average absolute deviations of better than 0.13%. 相似文献
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The effect of poly(ethylene glycol) as plasticizer in blends of poly(lactic acid) and poly(butylene succinate)
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Weraporn Pivsa‐Art Kazunori Fujii Keiichiro Nomura Yuji Aso Hitomi Ohara Hideki Yamane 《应用聚合物科学杂志》2016,133(8)
The effect of polyethylene glycol (PEG) on the mechanical and thermal properties of poly(lactic acid) (PLA)/poly(butylene succinate) (PBS) blends was examined. Overall, it was found that PEG acted as an effective plasticizer for the PLA phase in these microphase‐separated blends, increasing the elongation at break in all blends and decreasing the Tg of the PLA phase. Significant effects on other properties were also observed. The tensile strength and Young's modulus both decreased with increasing PEG content in the blends. In contrast, the elongation at break increased with the addition of PEG, suggesting that PEG acted as a plasticizer in the polymer blends. Scanning electron microscope images showed that the fracture mode of PLA changed from brittle to ductile with the addition of PEG in the polymer blends. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43044. 相似文献
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《木材化学与工艺学杂志》2013,33(3-4):249-260
Abstract Oil palm empty fruit bunch (EFB)-polyurethane (PU) composites were produced. The effects of the isocyanate (NCO)/glycol (OH) ratio, glycol type, and mixtures (polyethylene glycol PEG 400 (M w 400) and polypropylene glycol PPG 400 (M w 400)) on the flexural properties were investigated. The NCO/OH ratio had a significant effect on the flexural properties of the EFB-PU composites. Composites made with PEG 200 exhibited higher flexural properties than with PEG 400 and PPG 400. The flexural properties were also found to be influenced by the PPG 400/PEG 400 ratio. 相似文献
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Plasticizing effect of poly(ethylene glycol)s with different molecular weights in poly(lactic acid)/starch blends
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Binary and ternary blends composed of poly(lactic acid) (PLA), starch, and poly(ethylene glycols) (PEGs) with different molecular weights (weight‐average molecular weights = 300, 2000, 4000, 6000, and 10, 000 g/mol) were prepared, and the plasticizing effect and miscibility of PEGs in poly(lactic acid)/starch (PTPS) or PLA were intensively studied. The results indicate that the PEGs were effective plasticizers for the PTPS blends. The small‐molecule plasticizers of PEG300 (i.e., the Mw of PEG was 300g/mol) and glycerol presented better plasticizing effects, whereas its migration and limited miscibility resulted in significant decreases in the water resistance and elongation at break. PEG2000, with a moderate molecular weight, was partially miscible in sample PTPS3; this led to better performance in water resistance and mechanical properties. For higher molecular weight PEG, its plasticization for both starch and PLA was depressed, and visible phase separation also occurred, especially for PTPS6. It was also found that the presence of PEG significantly decreased the glass‐transition temperature and accelerated the crystallization of the PLA matrix, depending on the PEG molecular weight and concentration. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41808. 相似文献
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Melt blending of polylactic acid (PLA) and a chain‐extended polyethylene glycol (CE‐PEG) have been performed in an effort to toughen the PLA without significant loss of modulus and ultimate tensile strength. The chain‐extended PEG was prepared with melt condensation of a low molecular weight PEG and 4,4′‐methylenebis(phenylisocyanate) (MDI) for enhancement of the molecular weight of PEG. The thermal and mechanical properties, miscibility and phase morphologies of blends were investigated. By using thermal and fracture surface analysis, the blends were found to be a partially miscible system with shifted glass transition temperatures. The addition of CE‐PEG leads to slight decrease in tensile strength and modulus, while the elongation at break is characterized by an important increase (540%), compared with neat PLA and PLA/PEG (low molecular weight PEG, Mn = 35,000). The relative ductility of PLA/CE‐PEG is 40 times higher than that of neat PLA. The brittle fracture of neat PLA was transformed into a ductile fracture by the addition of CE‐PEG. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012 相似文献
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Environmental usefulness of PLA/PEG blends for controlled-release systems of soil-applied herbicides
Blends consisting of biodegradable polylactide (PLA) and poly(ethylene glycol) (PEG) were investigated for their usefulness as an environmentally friendly herbicide formulation with prolonged activity. The aim of this study was to evaluate the release rate of selected soil-applied herbicides from the PLA/PEG blend containing PEG of various molecular weights and to assess the phytotoxicity of the PEGs according to OECD 208 guidelines. The release rate of immobilized herbicides was correlated with degradation of the blends used. The progress of PLA/PEG blend degradation in water, soil, and activated sludge was estimated by sample weight loss, changes in blend composition, and microscopic observations of the blend surfaces during the experiment. The proposed formulation of the immobilized herbicide in a blend consisting of slowly biodegradable PLA and water-soluble PEG provides the possibility to release the herbicides for a relatively long time, for approximately six months, which is a demand of weed management. The effect of PEGs on plant growth and development was dependent on both their concentration and molecular weight. With a higher concentration in soil and a higher molecular weight of PEG, a more harmful effect on plants was noticed. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47856. 相似文献