辐射改性淀粉与PBAT共混体系的制备及表征

为提高淀粉与聚对苯二甲酸-己二酸丁二酯（PBAT）的共混性,对原淀粉进行辐射改性,以甘油作为增塑剂,制备热塑性淀粉（TPS）。以改性聚酯（WPT）作为高分子增容剂,将TPS与WPT以及PBAT混合均匀,进入双螺杆挤出机中进行混炼,制备TPS/PBAT共混物。采用扫描电镜、万能材料试验仪、X射线衍射仪、热重分析等表征样品力学性能与相容性。结果表明：辐射淀粉的加入使共混体系的相容有所改善。进一步引入增容剂,共混体系的结晶度和热稳定性下降,力学性能明显改善。当PBAT含量为15%,WPT含量为6%时,增容效果达到最佳,TPS/PBAT的拉伸强度为16.7 MPa,断裂伸长率为107.9%。     

改性热塑性淀粉的制备及其与PBAT复合薄膜的性能

利用十六烷基三甲氧基硅烷（HDTMS）对淀粉进行偶联改性后,通过熔融挤出得到热塑性淀粉（TPS）,并将其与聚己二酸/对苯二甲酸丁二醇酯（PBAT）复配后吹膜,制备了PBAT/TPS复合膜材料,并探讨了HDTMS含量与TPS耐热性能、流变性能及PBAT/TPS复合膜疏水性能和力学性能的关系。结果发现,加入HDTMS后TPS加工性能得到改善、淀粉基体耐热性能更高,但增塑剂更易析出;加入1份HDTMS后,PBAT/TPS复合膜材料疏水性能得到改善,接触角提高到113.2°,再继续增加HDTMS含量后,接触角基本保持在104°～106°;PBAT/TPS复合膜材料拉伸强度随HDTMS含量的增加先提高后降低,当HDTMS含量为3份时拉伸强度达10.29 MPa。     

PBAT/PLA/TPS生物降解薄膜的制备及性能研究

聚对苯二甲酸-己二酸-丁二醇酯(PBAT),聚乳酸(PLA)和热塑性淀粉(TPS)通过熔融共混并挤出吹膜。固定PBAT的质量分数为50%,改变PLA和TPS的比例。对PBAT/PLA/TPS薄膜的力学性能、热性能、结晶行为、撕裂断面形态、阻水性和氧气渗透性进行了研究。结果表明,PBAT/PLA/TPS薄膜中PLA的冷结晶温度降低了约40℃,PLA的冷结晶能力增强。随着TPS含量的增加,PBAT/PLA/TPS薄膜的拉伸强度降低、断裂伸长率增加。通过扫描电子显微镜观察,PBAT/PLA/TPS薄膜表现为明显的韧性断裂。水接触角和氧气渗透性测试表明薄膜具有良好的应用性能。     

热塑性共聚改性聚乙烯醇的结晶动力学

以丙三醇为增塑剂，通过双螺杆熔融挤出热塑化加工工艺，制备了丙三醇热塑化的热塑性共聚改性聚乙烯醇（TCPVA）。采用差示扫描量热法对TCPVA和热塑性常规聚乙烯醇（TPVA）的结晶行为进行了研究与对比，并利用莫志深方程和Avrami方程分别分析非等温结晶动力学和等温结晶动力学。结果表明：TCPVA的结晶温度、结晶速率、结晶活化能、结晶度、晶粒粒径较TPVA低，说明共聚改性基团会破坏分子链的规整性，即TCPVA不易结晶。     

聚丁二酸丁二酯/丙三醇增塑淀粉的制备及性能

用丙三醇增塑玉米淀粉制备热塑性淀粉,采用熔融共混法制备了聚丁二酸丁二酯(PBS)/丙三醇增塑玉米淀粉(GTPS)复合材料。用红外光谱(FTIR)、宽角-X射线衍射(WXRD)、扫描电镜(SEM)等方法研究了复合材料的相容性、结晶性能、力学性能、微观形貌及降解性能。结果表明:加入淀粉未改变PBS的晶型;丙三醇对淀粉的塑化只发生在淀粉的非晶区;加入淀粉,PBS的拉伸强度、断裂伸长率降低,冲击强度上升;随丙三醇含量上升,体系的力学性能下降。     

PBTA/TPS共混物的结构、性能和断裂行为

将热塑性淀粉(TPS)与聚(对苯二甲酸丁二醇酯-己二酸丁二醇酯)(PBAT)挤出共混并注塑成型,制备了可完全生物降解的TPS/PBAT复合材料制品。采用扫描电子显微镜研究了注塑复合材料的层次结构与微观形态,测试了不同组分复合材料的性能和应力应变行为。结果表明：TPS在PBAT中呈皮芯结构分布,随含量增加逐渐由芯层向皮层分布。当含量为45%时,芯层到皮层形成均匀的以纤维为主的分散相形态,提高了复合材料的力学性能。加入TPS后会改变复合材料的形变行为,由类似半结晶聚合物的应力应变行为转变为屈服-冷拉行为。     

复合增塑剂改性PBAT/淀粉薄膜的性能

以玉米淀粉、聚己二酸/对苯二甲酸丁二酯(PBAT)为主要原材料,甘油为主增塑剂,山梨醇、聚乙烯醇200(PEG200)、二甲基甲酰胺等为辅增塑剂,通过挤出机造粒再吹塑方法制成淀粉填充PBAT薄膜.研究对比了不同增塑剂在淀粉填充PBAT材料中的塑化效果,同时探究了不同塑化剂对复合薄膜力学性能、表面粗糙度、吸水率、溶出率及...     

热塑性淀粉共混改性PBAT纤维的制备及其性能研究

针对聚己二酸丁二醇酯-对苯二甲酸丁二醇酯(PBAT)在熔融纺丝时易发生热熔黏连、纤维强度低等问题，通过共混改性的方法引入热塑性淀粉(TPS),制备了TPS质量分数为1%、5%、10%的PBAT/TPS共混切片及共混纤维，对PBAT/TPS共混切片的稳定性、熔融结晶性能及共混纤维的形貌结构、力学性能和回弹性能进行了表征。结果表明：质量分数为1%、5%的TPS能够在PBAT中实现均匀分散，且TPS在PBAT中能够起到结晶成核剂的作用，提升PBAT结晶温度与结晶速率，同时TPS的多羟基结构能够连接起PBAT的分子链，提升PBAT熔体的稳定性与可纺性；在共混纺丝中，添加TPS质量分数为1%、拉伸倍数为2.4时，PBAT/TPS共混纤维表现出较好的力学性能及回弹性能，断裂强度达2.2 cN/dtex,断裂伸长率为96.8%,在30%定伸长下弹性回复率达97.67%。     

马来酸酐表面改性秸秆增强热塑性淀粉复合材料

首先用马来酸酐（MA）对小麦秸秆（WS）表面进行预处理,再经双螺杆挤出机在高温剪切作用下与玉米淀粉及增塑剂共混制备马来酸酐改性秸秆增强热塑性淀粉（MA-WS/TPS）复合材料,研究了MA的用量对MA-WS/TPS的力学性能,断面形貌,热稳定性和耐水性的影响。结果表明,WS经不同用量的MA改性后, 以1wt% 添加于MA-WS/TPS中,使复合材料的性能改善明显。当MA用量为4wt%时,其拉伸强度和断裂伸长率达到最佳（2.76MPa和158.24%）;热稳定性方面,MA改性使WS/TPS复合材料的最大热分解速率有所提高;此外,接触角结果表明, MA处理使得复合材料的耐水性显著提高,当MA用量为6wt%时,接触角可达到83.6°。综合性能以MA含量4wt%制得的复合材料最优。     

高淀粉含量玉米淀粉膜的制备及结构性能研究

为改善原淀粉膜的脆性和成膜性,以甘油为增塑剂、采用高速搅拌及流延法制备了高淀粉含量的玉米淀粉膜.研究了甘油增塑前后玉米淀粉膜的热性能、显微观察及结晶结构,以及甘油的添加量对淀粉糊的流变性及淀粉膜的机械性能影响.结果表明甘油塑化玉米淀粉膜的α型结晶结构被破坏,并随甘油量的增加玉米淀粉膜的结晶度下降;甘油塑化的淀粉糊为假塑性流体,其黏度随剪切速率的增加而降低.当淀粉/水质量比为0.06时,甘油加入量为淀粉质量的40%时,甘油塑化淀粉膜的综合力学性能较好.     

Microstructural characterization of corn starch‐based porous thermoplastic composites filled with multiwalled carbon nanotubes

Microstructural characterization of corn starch‐based porous thermoplastic (TPS) composites containing various contents (0.1, 0.5, and 1 wt %) of multiwalled carbon nanotubes (MWCNTs) was performed. Corn starch was plasticized with a proper combination of glycerol and stearic acid. TPS composites with MWCNT were prepared conducting melt extrusion followed by injection molding. TPS containing 1 wt % of MWCNTs exhibited higher tensile strength and elastic modulus values than neat TPS. Moreover, TPS electrical conductivity was determined to increase with increasing content of MWCNTs. X‐ray diffraction measurements revealed that incorporation of MWCNTs increased the degree of TPS crsystallinity to some extent. Scanning electron microscopy examination revealed that MWCNT altered TPS surface morphology and tensile failure modes, significantly. Transmission electron microscopy investigation showed that dispersion characteristics of MWCNTs within TPS were in the form of tiny clusters around micro pores of TPS, which is considered influential on electrical conductivity of the resulting composites. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Comparison of sorbitol and glycerol as plasticizers for thermoplastic starch in TPS/PLA blends

This article investigates the structure and properties of thermoplastic starch/PLA blends where the TPS phase is plasticized by sorbitol, glycerol, and glycerol/sorbitol mixtures. The blends were prepared using a twin‐screw extruder where starch gelatinization, water removal, and dispersion of TPS into a PLA matrix were carried out sequentially. The plasticizers were added to starch in the first stage of the extruder to allow complete starch gelatinization. The PLA was added at mid‐extruder and thoroughly mixed with the TPS. The plasticizer concentration was varied from 30 to 42% and the TPS content was varied from 27 to 60% on a weight basis. In all investigated blends, the PLA formed the continuous phase and the TPS was the dispersed phase. The viscosity, blend morphology, tensile mechanical properties as well as the thermal properties of the materials were measured. It was found that the glycerol/sorbitol ratio has an important effect on the blend properties. Finer blend morphologies, higher tensile strength and modulus but lower crystallization rate were found for the sorbitol plasticized blends. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Preparation and properties of thermoplastic pea starch using N,N‐bis(2‐hydroxyethyl)formamide as the plasticizer

N,N‐bis(2‐hydroxyethyl)formamide (BHF) was synthesized efficiently and used as a new plasticizer for pea starch to prepare thermoplastic starch (TPS). The hydrogen bond interaction between BHF and pea starch was proven by Fourier‐transform infrared (FT‐IR) spectroscopy. As detected by scanning electron microscope (SEM), pea starch granules were completely disrupted, and the homogeneous materials were obtained. The crystallinity of pea starch and BHF‐plasticized thermoplastic pea starch (BTPS) was characterized by X‐ray diffraction (XRD). Rheological properties of TPS were analyzed. The water resistance of BTPS was better than that of glycerol‐plasticized thermoplastic pea starch (GTPS). At RH 33%, the tensile strength of BTPS was higher than that of GTPS for TPS containing 30% plasticizer. POLYM. ENG. SCI., 2010. © 2009 Society of Plastics Engineers     

Formamide as the plasticizer for thermoplastic starch

As a novel plasticizer, formamide was tested in thermoplastic starch (TPS), in which native cornstarch granules were proved to transfer to a continuous phase by scanning electron microscope (SEM) and the hydrogen bond interaction between plasticizer and starch was proved by Fourier transform infrared (FTIR) spectroscopy. Mechanical tests showed that tensile strength and Young's modulus of formamide‐plasticized TPS (FPTPS) were lower than glycerol‐plasticized TPS (GPTPS) and elongation at break and energy break were higher. The effect of formamide and glycerol on the retrogradation of TPS was studied using X‐ray diffractometry. Formamide could effectively restrain the starch retrogradation at three different relative humidity (RH) environments, because it could form the more stable hydrogen bonds with the starch hydroxy group than glycerol. From these results, we found that the elongation at break, energy break, and the retrogradation of TPS were ameliorated by formamide. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 1769–1773, 2004     

Thermoplastic corn starch reinforced with cotton cellulose nanofibers

This work evaluates the use of cotton cellulose nanofibers (CCN) as a reinforcing agent to prepare thermoplastic corn starch (TPS) matrix plasticized with 30 wt % of glycerol. The nanocomposites were filled with 0.5–5.0 wt % of CCN on a dry‐starch basis. The dried nanofibers were resuspended through the use of an ultrasonicator and then introduced in the fixed water formulation for obtaining TPS. The nanocomposites were compounded in a corotating twin‐screw extruder. Scanning transmission electron microscopy (STEM), field emission gun (FEG), X‐ray diffraction (XRD) and thermogravimetric analysis (TGA), in air atmosphere, were used to characterize nanofibers, neat TPS, and nanocomposites. The results showed that the nanofibers had needlelike structure with an average length of about 135 ± 50 nm and an average diameter of about 14 ± 4 nm. The addition of CCN was effective to enhance the mechanical properties of neat TPS in compositions above 2.5 wt %, although some agglomeration could be observed. The resulting nanocomposites showed good structural stability, because the amylopectin transcrystallization phenomena on the surface of nanofibers had not occurred. Only a slight decrease in the crystallinity index and a minor increase in the water absorption in relation to neat TPS were observed. An increase in the thermal stability of TPS nanocomposites with respect to neat TPS was verified, but it was independent of the CCN content. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

TPS／PBAT共混体系的结构、性能和形态研究

通过熔融共混制备了系列TPS／PBAT复合材料,研究了TPS含量对TPS／PBAT结构、力学性能、耐热性能和微观形态的影响,结果表明：PBAT可以明显提高TPS的拉伸强度、断裂伸长率和耐热温度,但TPS和PBAT两相相容性较差。     

热塑性淀粉增韧改性聚酰胺6的研究

将甘油增塑玉米淀粉制得的热塑性淀粉（TPS）与聚酰胺6（PA6）进行熔融共混,制备PA6/TPS共混物,研究不同含量的甘油和TPS对PA6/TPS共混物性能的影响,并探讨TPS增韧PA6的机理。采用万能试验机、溶体流动速率仪和扫描电子显微镜对改性PA6进行表征。结果表明,加入TPS后,共混物的冲击强度和拉伸模量有所提高,而拉伸强度和熔体流动速率略有下降,表明TPS对PA6起到了有机刚性粒子增韧的作用;TPS对PA6的增韧机理主要是界面脱黏、空化作用;甘油含量对TPS改性PA6的韧性影响显著,甘油含量为25 %的TPS添加量为25 %时,其增韧效果最好,冲击强度比PA6提高了63 %。     

淀粉/WPUR生物可降解塑料的制备与性能

以玉米淀粉与水性聚氨酯(WPUR)为主要原料,以甘油为增塑剂,采用熔融共混工艺制备了生物可降解热塑性淀粉塑料(TPS)/WPUR共混物。考察了TPS/WPUR共混物的微观结构、成型加工性能、力学性能和耐水性能等。结果表明,WPUR不仅有利于TPS的塑化和改善其熔体流动性,而且也有利于提高其拉伸性能和耐水性。