Boltorn型超支化聚酯对PHBV的增韧改性研究

以对甲苯磺酸(p?TSA)为催化剂,三羟甲基丙烷(TMP)为核、2,2?二羟甲基丙酸(DMPA)AB2型单体为主要原料,采用“一步法”合成了Boltorn型超支化聚酯(HBPE);以HBPE为改性剂,以三氯甲烷为溶剂,通过溶液法对聚(3?羟基丁酸酯?co?3?羟基戊酸酯) (PHBV)树脂进行改性,并通过差示扫描量热仪、力学性能测试、热台偏光显微镜、热重分析仪、扫描电子显微镜等分析方法对其进行表征。结果表明,随着HBPE加入量的增加,PHBV体系的玻璃化转变变得越来越明显,表明HBPE的加入显著增强了PHBV的链段运动能力;当HBPE添加量为4份时,PHBV体系的结晶度由64.77 %下降至27.68 %,断裂伸长率提高了194.04 %,拉伸强度提高了27.22 %,撕裂强度提高了56.28 %;HBPE的加入,在保持PHBV树脂拉伸强度小幅增强的基础上,使得PHBV的断裂韧性得到明显提升;HBPE是一种优良的PHBV增韧改性材料。     

PHBV/PBS共混物的性能研究

通过熔融共混的方法制备了聚β-羟基丁酸戊酸酯/聚丁二酸丁二醇酯(PHBV/PBS)共混材料。研究了PHBV/PBS共混物的力学性能、相形态、结晶性能、热性能及晶胞结构。结果表明,将PHBV和PBS共混后,PHBV的韧性会有明显改善。当PHBV/PBS/TEC质量比为20/80/5时,PHBV的断裂伸长率由原来的5.7%增至124%、冲击强度由1.7 kJ/m2增加到4.3 kJ/m2,分别为PHBV的21.7倍和2.5倍。DSC研究表明,PBS的加入抑制了PHBV的结晶,但当PHBV/PBS/TEC质量比为20/80/5时,共混物出现了共晶现象。XRD显示PBS的加入在一定程度上影响了PHBV的晶型,复合材料的晶面特征峰发生了明显偏移。     

OMMT对PHBV/EVA共混物的改性研究

以有机改性蒙脱土（OMMT）为改性剂,采用熔融共混法制备了聚（3-羟基丁酸酯-co-3-羟基戊酸酯）/乙烯-乙酸乙烯酯/有机改性蒙脱土（PHBV/EVA/OMMT）共混物和样条,并通过旋转流变仪、差示扫描量热仪（DSC）、红外光谱仪（FTIR）、万能试验机、热失重分析仪（TG）、偏光显微镜（PLM）和扫描电子显微镜（SEM）等对其流变性能、结晶性能、力学性能、热性能及微观形貌等进行了表征。结果表明,随着OMMT含量的增加,PHBV/EVA/OMMT共混物的损耗模量和复数黏度增大;在PHBV/EVA/OMMT共混物中,OMMT产生了插层结构;OMMT的加入破坏了PHBV/EVA共混物的结晶,使其结晶度降低;当OMMT含量为7份（质量份,下同）时,PHBV/EVA/OMMT的结晶度最低,为43.4 %;随着OMMT含量的增加,PHBV/EVA/OMMT样条的断裂伸长率和冲击强度先升高后降低,当OMMT含量为3份时,其断裂伸长率较PHBV/EVA提升了38.3 %,冲击强度提升了52.5 %;加入OMMT后,PHBV/EVA样条的冲击断面变得更加粗糙。     

MgO对PHBV结晶和热行为的影响

采用于法共混工艺制备了聚(β-羟基丁酸酯-co-β羟基戊酸酯)/轻质氧化镁复合材料(PHBV/MgO),通过 DSC、POM、XRD 和 TGA 等手段研究了 MgO 对 PHBV 结晶、熔融和热分解行为的影响,验证了高温下 PHBV 和MgO 之间的相互作用。DSC 结果表明,MgO 的加入阻碍了 PHBV 的结晶过程,使其结晶温度和结晶度降低;POM观察到 MgO 的加入使 PHBV 球晶尺寸显著减小,同时球晶密度明显增加;PHBV/MgO 复合材料中部分 PHBV 基体的起始热分解温度比纯 PHBV 提高140℃以上。熔融态下等温 DSC 曲线还表明,MgO 与 PHBV 在高温下能够发生化学反应。     

扩链剂TMP-6000对聚乳酸/聚（3-羟基丁酸-co-3 -羟基戊酸酯）共混物性能的影响

以扩链剂TMP-6000为增容剂,采用熔融共混制备了聚乳酸（PLA）和聚（3羟基丁酸co3羟基戊酸酯）（PHBV）复合材料,研究了TMP-6000对PLA/PHBV复合材料的结晶行为、微观结构、力学性能的影响。结果表明,无定形PLA的加入抑制了PHBV的结晶,TMP-6000的加入使得PLA/PHBV复合材料的结晶能力变弱,提高了PLA的冷结晶温度,且当TMP-6000含量为0.5 %（质量分数,下同）时,PLA的冷结晶峰开始消失,且适量的TMP-6000使得PHBV的玻璃化转变温度（Tg）升高;TMP-6000的加入使得PHBV均匀分散于PLA基体中,且当TMP-6000含量为0.7 %时,PLA与PHBV的相容性最好;TMP-6000的加入显著提高了PLA/PHBV复合材料的分子量;TMP-6000提高了PLA与PHBV之间的结合力,提高了复合材料的拉伸强度,但断裂伸长率有稍微地降低。     

聚酰胺-胺树形分子的合成及其包覆的CdSe@CdS核壳结构量子点的性能研究

以乙二胺和丙烯酸甲酯为原料,采用扩散法合成了不同端基类型不同代数的聚酰胺-胺(PAMAM)树形高分子,并用红外光谱进行表征;以G5.0-NH2 PAMAM树形高分子为模板,以二甲基亚砜为溶剂,在常温下制备了稳定的PAMAM树形高分子包覆的CdSe@CdS核壳结构量子点,并用紫外-可见吸收光谱和荧光发射光谱进行表征。结果表明,适当厚度CdS的包覆修饰可以有效提高CdSe量子点的发光性能;与单一组分的CdSe量子点相比,CdSe@CdS核壳结构量子点的相对荧光强度最大提高约123 %。     

端环氧型超支化聚酯对聚（3-羟基丁酸戊酸共聚酯）的改性研究

以2,2二羟甲基丙酸（DMPA）和三羟甲基丙烷（TMP）为原料,以对甲苯磺酸（P-TSA）为催化剂,通过“一步法”合成三代超支化聚酯（HBPE）,然后采用环氧氯丙烷对HBPE进行改性,得到了具有端环氧基的三代超支化聚酯（EHBP-G3）目标产物,最后采用熔融共混法制备了EHBP改性的聚（3-羟基丁酸酯-co-3羟基戊酸酯）（PHBV）树脂;通过差示扫描量热仪、偏光显微镜、力学性能和熔体流动速率等分析方法对制备的PHBV/EHBP共混物进行表征。结果表明,加入1.5 %(质量分数,下同)三代超支化聚酯（EHBP-G3）时,PHBV/EHBP共混物的结晶度下降了16.1 %,冲击强度提高了34.3 %。     

成核剂对PHBV结晶影响的研究

通过熔融共混的方法,分别将成核剂A、成核剂B、氧化锌(ZnO)、二氧化硅(SiO₂)与聚-3-羟基丁酸/戊酸酯(PHBV)进行共混,研究了它们对PHBV结晶性能的影响。利用差示扫描量热仪研究了复合材料的等温结晶和非等温结晶动力学,利用热台偏光显微镜观察了晶体成核和生长过程。结果表明,这些成核剂均可以改善PHBV结晶不完善的情况,使PHBV的熔融峰从2个变为1个;成核剂A和B可改善PHBV的成核效果,提高PHBV的结晶速率,且球晶尺寸明显细化;加入SiO₂后,形成了同心圆球晶,结晶速率获得改善。     

聚羟基丁酸戊酸酯溶液共混改性研究

采用溶液共混方法来制备聚羟基丁酸戊酸酯(PHBV)生物降解薄膜,通过与不同材料共混,实现对PHBV薄膜的增韧改性.通过对共混膜力学性能、透光率的测定、红外光谱分析、扫描电镜观察,得出实验结果Ecoflex含量达到50%时,PHBV/Ecoflex薄膜韧性得到明显改善;PHBV/双酚A(BPA)溶液共混体系之间有氢键形成;PHBV/羟丙基交联改性淀粉体系,为不相容体系,其力学、光学性能明显下降.     

PHBV增韧PLA的结晶及力学性能研究

采用熔融共混法,以聚(3-羟基丁酸-co-3-羟基戊酸酯)(PHBV)为增韧剂对聚乳酸(PLA)进行改性,得到PLA/PHBV复合材料。研究了PHBV用量对PLA/PHBV复合材料结晶性能和力学性能的影响。结果表明:随着PHBV用量的增加,PLA/PHBV复合材料的结晶度逐渐减小,拉伸强度和弯曲强度逐渐降低,而断裂伸长率则逐渐增大(当PHBV用量为50%时,复合材料的断裂伸长率比纯PLA提高了1.72倍),同时复合材料的冲击强度亦有所提高。由此可见,在不明显降低拉伸强度和弯曲强度的前提下,适量PHBV的添加能够改善PLA/PHBV复合材料的韧性。     

Preparation of CaCO3/polymer composite films via interaction of anionic starburst dendrimer with poly(ethylenimine)

Summary The CaCO₃/poly(ethylenimine) composite film was obtained in the presence of anionic poly(amidoamine) (PAMAM) dendrimer (G=3.5), whereas the formation of composite film was not observed without PAMAM dendrimer or with PAMAM dendrimer (G=1.5) judging from the results of scanning electron micrographs (SEM). The crystal phase of the CaCO₃ film formed was found to be calcite by FT-IR and XRD analysis. The adsorption of PAMAM dendrimer on poly(ethylenimine) film might cause local high concentration of calcium ion and induce a formation of the CaCO₃ film. Received: 23 October 2000/Accepted: 10 November 2000     

PAMAM树形分子在油墨废水处理中的应用研究

使用聚酰胺-胺(PAMAM)树形分子处理油墨废水,研究了树形分子的代数、溶液的酸度以及树形分子的加药量对色度和COD去除率的影响。研究表明,PAMAM树形分子对油墨废水具有良好的治理效果,在pH值为5.0左右,PAMAM投加量为20mg/L的条件下色度和COD去除率可分别达到98.6%和98.3%。     

PHB和PHBV增韧、增塑改性研究进展

总结了近年来国内外关于聚羟基丁酸酯(PHB)和聚羟基丁酸酯-co-羟基戊酸酯共聚物(PHBV)在增韧和增塑改性方面的研究进展。通过应力-应变行为和冲击强度等性能指标,对弹性体、酚类化合物、反应性增韧、超高相对分子质量聚乙二醇、淀粉、羟基烷酸酯、热处理等增韧改性方法和效果、改性产物进行了评述；通过熔点、玻璃化转变温度、冷结晶温度等性能指标,对共聚改性、中小相对分子质量聚乙二醇、环氧大豆油等增塑剂增塑改性方法、效果以及改性产物进行了详细介绍。最后对PHB和PHBV生物降解材料的发展前景进行了展望。     

低代数聚丙烯亚胺树形分子的合成与表征

对聚丙烯亚胺树形分子的合成进行了研究。通过优化反应条件 ,如提高反应温度、增大反应物浓度、加入少量醋酸作为催化剂、选择氨 甲醇作为还原溶剂 ,提出了一条合成结构较为精确 ,可以最大程度减少或避免副反应的聚丙烯亚胺树形分子的合成路线。红外光谱表明优化条件下所得 0 5代聚丙烯亚胺树形分子反应完全 ,有利于结构增长 ;滴定法表明在氨 甲醇溶剂下还原所得 1 0代聚丙烯亚胺树形分子中伯胺基的摩尔分数为x (NH2 ) =85 % ,比在甲醇条件下所得结果 [x(NH2 ) =76 % ]有较大提高。1H核磁共振、元素分析也表明所合成的低代数聚丙烯亚胺树形分子结构精确 ,达到了分子设计的目的。     

Thermal properties of blends of poly(hydroxybutyrate‐co‐hydroxyvalerate) and poly(styrene‐co‐acrylonitrile)

Thermal properties of blends of poly(hydroxybutyrate‐co‐hydroxyvalerate) (PHBV) and poly(styrene‐co‐acrylonitrile) (SAN) prepared by solution casting were investigated by differential scanning calorimetry. In the study of PHBV‐SAN blends by differential scanning calorimetry, glass transition temperature and melting point of PHBV in the PHBV‐SAN blends were almost unchanged compared with those of the pure PHBV. This result indicates that the blends of PHBV and SAN are immiscible. However, crystallization temperature of the PHBV in the blends decreased approximately 9–15°. From the results of the Avrami analysis of PHBV in the PHBV‐SAN blends, crystallization rate constant of PHBV in the PHBV‐SAN blends decreased compared with that of the pure PHBV. From the above results, it is suggested that the nucleation of PHBV in the blends is suppressed by the addition of SAN. From the measured crystallization half time and degree of supercooling, interfacial free energy for the formation of heterogeneous nuclei of PHBV in the PHBV‐SAN blends was calculated and found to be 2360 (mN/m)³ for the pure PHBV and 2920–3120 (mN/m)³ for the blends. The values of interfacial free energy indicate that heterogeneity of PHBV in the PHBV‐SAN blends is deactivated by the SAN. This result is consistent with the results of crystallization temperature and crystallization rate constant of PHBV in the PHBV‐SAN blends. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 673–679, 2000     

Miscibility and crystallization behavior of biodegradable blends of two aliphatic polyesters. Poly(3-hydroxybutyrate-co-hydroxyvalerate) and poly(ε-caprolactone)

Biodegradable polymer blends of poly(3-hydroxybutyrate-co-hydroxyvalerate) (PHBV) and poly(ε-caprolactone) (PCL) blends were prepared with the ratio of PHBV/PCL ranging from 80/20-20/80 by co-dissolving the two polyesters in chloroform and casting the mixture. Differential scanning calorimetry (DSC) and optical microscopy (OM) were used to investigate the miscibility and crystallization of PHBV/PCL blends. Experimental results indicated that PHBV showed no miscibility with PCL for PHBV/PCL blends as evidenced by the existence of unchanged composition independent glass transition temperature and the biphasic melt. Crystallization of PHBV and PCL was studied with DSC and analyzed by the Avrami equation by using two-step crystallization in the PHBV/PCL blends. The crystallization rate of PHBV at 70 °C decreased with the increase of PCL in the blends, while the crystallization mechanism did not change. In the case of the isothermal crystallization of PCL at 42 °C, the crystallization rate increased with the addition of PHBV, and the crystallization mechanism changed, too, indicating that the crystallization of PHBV at 70 °C had an apparent influence on the crystallization of PCL at 42 °C.     

Hydrothermal-Freeze-Casting of Poly(amidoamine)-Modified Graphene Aerogels towards CO2 Adsorption

This article presents novel poly(amidoamine) (PAMAM) dendrimer-modified with partially-reduced graphene oxide (rGO) aerogels, obtained using the combined solvothermal synthesis-freeze-casting approach. The properties of modified aerogels are investigated with varying synthesis conditions, such as dendrimer generation (G), GO:PAMAM wt. ratio, solvothermal temperature, and freeze-casting rate. Scanning electron microscopy, Fourier Transform Infrared spectroscopy, Raman spectroscopy, X-ray photoelectron spectroscopy are employed to characterize the aerogels. The results indicate a strong correlation of the synthesis conditions with N content, N/C ratio, and nitrogen contributions in the modified aerogels. Our results show that the best CO₂ adsorption performance was exhibited by the aerogels modified with higher generation (G7) dendrimer at low GO:PAMAM ratio as 2:0.1 mg mL⁻¹ and obtained at higher solvothermal temperature and freeze-casting in liquid nitrogen. The enclosed results are indicative of a viable approach to modify graphene aerogels towards improving the CO₂ capture.     

Miscibility and crystallization behaviour of biodegradable blends of two aliphatic polyesters. Poly(3-hydroxybutyrate-co-hydroxyvalerate) and poly(butylene succinate) blends

Blends of poly(3-hydroxybutyrate-co-hydroxyvalerate) (PHBV) and poly(butylene succinate) (PBSU), both biodegradable semicrystalline polyesters, were prepared with the ratio of PHBV/PBSU ranging from 80/20 to 20/80 by co-dissolving the two polyesters in chloroform and casting the mixture. Differential scanning calorimetry (DSC) and optical microscopy (OM) were used to study the miscibility and crystallization behaviour of PHBV/PBSU blends. Experimental results indicate that PHBV is immiscible with PBSU as shown by the almost unchanged glass transition temperature and the biphasic melt. Crystallization of PHBV/PBSU blends was studied by DSC using two-step crystallization and analyzed by the Avrami equation. The crystallization rate of PHBV decreases with the increase of PBSU in the blends while the crystallization mechanism does not change. In the case of the isothermal crystallization of PBSU, the crystallization mechanism does not change. The crystallization rate of PBSU in the blends is lower than that of neat PBSU; however, the change in the crystallization rate of PBSU was not so big in the blends. The different content of the PHBV in the blends does not make a significant difference in the crystallization rate of PBSU.