聚碳酸亚丙酯扩链研究

分别以ADR-4380、二苯基甲烷二异氰酸酯(MDI)、三苯基甲烷四异氰酸酯(DTTI)、三苯基甲烷三异氰酸酯(TTI)和硫代磷酸三苯基异氰酸酯(TPTI)为扩链剂,利用HAAKE混合器研究了它们对聚碳酸亚丙酯的扩链效果。结果表明,ADR-4380对聚碳酸亚丙酯树脂没有明显的扩链作用,而MDI、DTTI、TTI和TPTI都对聚碳酸亚丙酯树脂有明显的扩链作用,且扩链效果顺序是:DTTI>TPTI>TTI>MDI。扩链温度也是影响聚碳酸亚丙酯扩链效果的重要因素,不同扩链剂的最佳扩链温度不同,TPTI和TTI的最佳扩链温度为160℃,而DTTI和MDI的最佳扩链温度为170℃。     

聚碳酸亚丙酯增韧聚乳酸研究

利用双螺杆挤出机研究了聚碳酸亚丙酯(PPC)对聚乳酸(PLA)的增韧效果.结果表明:PPC树脂对PLA有明显的增韧作用,但增韧的同时会引起PLA拉伸强度和维卡软化温度的降低,随PPC用量增加,冲击强度持续提高,而拉伸强度和维卡软化温度持续降低;PLA/PPC共混体系中加入二苯基甲烷二异氰酸酯(MDI)后,可提高两者的相容性,从而起到增韧的作用,随MDI用量增加,PLA/PPC共混物的冲击强度和拉伸强度呈现先增加后减小的趋势.     

二异氰酸酯对聚碳酸亚丙酯熔体流变性能的影响

以4,4-二苯基甲烷二异氰酸酯（MDI）为扩链剂,在转矩流变仪上通过一步法对聚碳酸亚丙酯（PPC）进行了熔融扩链改性。结果表明,随着MDI用量的增加,扩链反应峰和平衡扭矩逐渐增大、平衡时间不断延长;红外光谱分析表明,扩链改性后的PPC在1600 、1535 cm-1处分别出现了苯环的骨架振动吸收峰和-NH的特征吸收峰;旋转流变分析表明,扩链改性后PPC的储能模量、损耗模量和复数黏度均随MDI用量的增加而增加;从Cole-Cole曲线可以看出,随着MDI用量的增加,扩链改性后PPC的相对分子质量逐渐增加,相对分子质量分布变宽,支化度提高;应力松弛测试结果表明,随着MDI用量的增加,松弛时间逐渐增加。     

改性聚碳酸亚丙酯研究进展

对可降解塑料聚碳酸亚丙酯(PPC)进行改性是改善其力学性能和热学性能的有效方法.综述了近年来改性PPC的研究机理,介绍了PPC的合成机理和热降解机理,主要阐述了PPC物理改性和化学改性方法.物理方法主要包括碳纤维、碳酸钙、改性纳米二氧化硅、纳米粘土、纤维素、有机蒙脱土(OMMT)等材料与PPC进行共混改性,化学方法主要...     

聚碳酸亚丙酯凝聚洗涤新工艺研究

针对3 000 t/a聚碳酸亚丙酯(PPC)工业装置凝聚洗涤存在的问题,研究开发了一种新的PPC凝聚洗涤工艺,采用闪蒸脱挥、喷雾凝聚和多釜串联洗涤工艺,可提高PPC聚合物的凝聚洗涤效果,提升PPC生产技术水平。     

聚碳酸亚丙酯凝聚洗涤问题研究

针对中海油3000t/a聚碳酸亚丙酯(PPC)工业装置的凝聚洗涤工序存在的问题,研究提出了改进PPC凝聚洗涤工艺的方案。包括凝聚乳化和多次洗涤工艺两部分,可以有效提高PPC洗涤效率,使得PPC产品的灰分含量和挥发分含量降至0.5%以下。     

聚碳酸亚丙酯的合成研究进展

聚碳酸亚丙酯是一种新型可完全生物降解的热塑性脂肪族聚碳酸酯。文章主要介绍了最近几年CO2与环氧丙烷交替共聚合成聚碳酸亚丙酯的研究进展,重点对其催化剂体系进行了详细的叙述和概括,并提出了聚碳酸亚丙酯的发展趋势。     

聚碳酸亚丙酯共混改性研究进展

聚碳酸亚丙酯(polypropylene carbonate,PPC)是一种新型可完全生物降解的热塑性脂肪族聚碳酸酯。与其它聚合物进行共混改性是改善PPC基材综合性能的有效手段。本文从PPC的合成工艺、性能特点和应用出发,综述了近十年来PPC与可降解聚合物、非降解聚合物、无机粒子等进行溶剂共混和熔融共混改性的研究进展;并对PPC将来的发展作了展望。     

改性聚碳酸亚丙酯的研究现状

二氧化碳与环氧丙烷共聚得到可生物降解的聚碳酸亚丙酯,聚碳酸亚丙酯是一种新型热塑性脂肪族聚碳酸酯,具有良好的生物相容性和降解性。但是聚碳酸亚丙酯的热力学稳定性和力学性能不好,必须对其改性。综述了聚碳酸亚丙酯的常用改性方法并对改性聚碳酸亚丙酯的发展做了展望。     

有机硅改性聚碳酸亚丙酯

以聚碳酸亚丙酯（PPC）和甲苯二异氰酸酯（TDI）以及官能性的有机硅烷为原料，通过聚氨酯预聚体的方法得到了硅烷化的聚碳酸亚丙酯（SPPC），利用有机硅官司能团的可水解性，可使SPPC交联而固化得到弹性体。     

Evidence of compatibility and thermal stability improvement of poly(propylene carbonate) and polyoxymethylene blends

Poly(propylene carbonate) (PPC) is a promising new sustainable polymer produced from carbon dioxide. PPC has inferior thermal stability which could be enhanced by synergistic blending with other polymers. Blends of PPC and the engineering thermoplastic polyoxymethylene are produced by melt compounding in various weight ratios. The compatibility of the blends is investigated using thermogravimetric analysis (TGA), differential scanning calorimetry, Fourier transform infrared spectroscopy (FTIR), density measurements, and scanning electron microscopy (SEM). TGA reveals that thermal stability of the blends increases dramatically in comparison to the neat PPC. A small shift in the glass transition temperature demonstrates the immiscibility of the blends but also indicates some compatibility, attributed to potential dipole–dipole interactions which are also corroborated with the FTIR results. A deviation of the rule of mixtures for density is found for some of the blends. SEM analysis of the blends shows two phase morphology; however, the interfacial adhesion appeared to be enhanced with increasing PPC content. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45823.     

Improved thermal stability and mechanical properties of poly(propylene carbonate) by reactive blending with maleic anhydride

To extend the application of a carbon dioxide sourced environmental friendly polymer: poly (propylene carbonate) (PPC), a small amount of maleic anhydride (MA) was melt blended to end‐cap with PPC to improve its thermal stability and mechanical properties. Thermal and mechanical properties of end‐capped PPC were investigated by TGA, GPC, mechanical test, and DMA. TGA and titration results demonstrate that PPC can be easily end‐capped with MA through simple melt blending. TGA results show that the thermal degradation temperature of PPC could be improved by around 140°C by adding MA. GPC measurement indicates that the molecular weight of PPC can be maintained after blending with MA, where pure PPC experiences a dramatic degradation in molecular weight during melt process. More importantly, the tensile strength of PPC after blending with MA was found to be nearly eight times higher than that of pure PPC. It has approached the mechanical properties of polyolefin polymers, indicating the possibility of replacing polyolefin polymers with PPC for low temperature applications. The method described here could be used to extend the applications of PPC and fight against the well known global warming problem. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Epoxy resins toughened by poly(propylene carbonate)

Poly(propylene carbonate) (PPC) was used as a toughening agent for improving the brittleness of cured epoxy resins (EP). Methyl tetrahydrophthatic anhydride (MTHPA) was used as a curing agent. The activation energies for the reactions of PPC/MTHPA and EP/MTHPA measured by FTIR were 115.8 and 66.5 kJ/mol, respectively, while for the composite system of PPC/EP/MTHPA, the activation energy obtained from DSC was 52.9 kJ/mol. Gel contents, DMA, and DSC displayed that the cured resins of PPC/EP/MTHPA were phase-separation crosslinking systems and most of PPC could react with MTHPA or the epoxy group. The toughness of cured resins was reinforced by the addition of PPC. The optimum mechanical properties and toughness for cured resins of PPC/EP/MTHPA corresponded to the system containing 20 phr PPC, which achieved a 33% increase in tensile strength and a 45% increase in the fracture toughness at no expense of the elongation of cured resins. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 64: 2457–2465, 1997     

Effects of l‐aspartic acid and poly(butylene succinate) on thermal stability and mechanical properties of poly(propylene carbonate)

Poly(propylene carbonate) (PPC) was modified by l ‐aspartic acid (Asp) and poly(butylene succinate) (PBS). To assess the effects of Asp and PBS on the thermal stability, mechanical properties of PPC, different PPC/Asp, PPC/PBS, and PPC/PBS/Asp blends were prepared by twin‐screw extruder. The results indicated that the thermal stability improved with the Asp content increasing from 0.5 to 5%. With trace presence of 2% Asp, the degradation temperature of PPC was greatly increased upon extruding and the Yield strength and Young's modulus increased 62 and 849 times, respectively, at 20°C. The flexibility of PPC was effectively improved by blending with PBS, the PBS has no significant effect on the thermal stability of PPC until PBS up to enough amount. Besides the Asp additive in PPC/PBS blends not only improved the thermal stability PPC, but improved the interfacial compatibility of the blend. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 42970.     

Improving the thermal and mechanical properties of poly(propylene carbonate) by incorporating functionalized graphite oxide

Poly(propylene carbonate) (PPC) is a new biodegradable aliphatic polycarbonate. However, the poor thermal stability, low glass transition temperatures (T_g), and relatively low mechanical property have limited its applications. To improve the thermal and mechanical properties of PPC, functionalized graphite oxide (MGO) was synthesized and mixed with PPC by a solution intercalation method to produce MGO/PPC composites. A uniform structure of MGO/PPC composites was confirmed by X‐ray diffraction and scanning electron microscope. The thermal and mechanical properties of MGO/PPC composites were investigated by thermal gravimetric analysis, differential scanning calorimetric, dynamic mechanical analysis, and electronic tensile tester. Due to the nanometer‐sized dispersion of layered graphite in polymer matrix, MGO/PPC composites exhibit improved thermal and mechanical properties than pure PPC. When the MGO content is 3.0 wt %, the MGO/PPC composites shows the best thermal and mechanical properties. These results indicate that nanocomposition is an efficient and convenient method to improve the properties of PPC. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

聚乳酸端羟基扩链研究

采用两步法工艺对乳酸进行了扩链聚合。首先将聚乳酸熔融后,用1,4-丁二醇进行醇酸缩合,制成羟基封端的预聚物;然后加入甲苯-2,4-二异氰酸酯进行扩链生成高相对分子质量的聚乳酸,并通过IR、~1H-NMR和DSC等方法对产物进行了表征。最佳反应工艺条件:与预聚物等摩尔量的1,4-丁二醇,辛酸亚锡催化,n_(NCO)∶n_(OH)为1∶1,160℃真空条件下反应100 min。聚乳酸的相对分子质量提高两倍以上,同时玻璃化转变温度由59℃提高到63℃。     

Preparation of chlorinated poly(propylene carbonate) and its effects on the mechanical properties of poly(propylene carbonate)/starch blends as a compatibilizer

Polymer Bulletin - Poly(propylene carbonate) (PPC) was chemically modified by chlorine through water phase suspension chlorination reaction, and the product was named as chlorinated poly(propylene...     

Morphology, thermal stability and rheology of poly(propylene carbonate)/organoclay nanocomposites with different pillaring agents

Unpillared montmorillonite PGV and five organoclays (Nanocor's Nanomer I.44P, I.24TL and I.34TCN and Southern Clay Product's C25A and C30B) were high shear melt-blended (2.5 wt%) into poly(propylene carbonate) (PPC). Solubility parameters of the clay pillaring agents versus that of PPC were used to predict clay/PPC miscibilities and these were compared to XRD and TEM nanoclay dispersion measurements. Clays I.34TCN and C30B, with the highest predicted pillaring agent/PPC miscibilites, had partially exfoliated morphologies. Clays I.24TL, C25A and I.44P, with pillaring agents predicted to be less PPC miscible, were less highly nanodispersed. Quaternary ammonium pillars with two 2-hydroxyethyl groups promoted the best nanodispersion in PPC. 12-Aminododecanoic acid (in I.24TL) promoted the intercalation. Dimethyl dialkyl quaternary ammoniums (in I.44P and C25A) were less effective. Organoclay dispersion improved the thermal stability. The PPC/I.24TL nanocomposite, with the most stable 12-aminododecanoic acid pillar, was the most thermally stable (PPC/I.34TCN and PPC/C30B were the second and third). The nanocomposites exhibited narrower linear viscoelastic zones than PPC and solid-like behaviors in these linear zones.