生物基聚3-羟基丁酸-戊酸酯/聚乳酸共混纤维的鉴别方法研究

根据FZ/T 01057.2—2007,FZ/T 01057.3—2007,FZ/T 01057.4—2007,FZ/T 01057.8—2012标准,采用燃烧法、显微镜法、溶解法和红外光谱法对聚3-羟基丁酸-戊酸酯/聚乳酸(PHBV/PLA)共混纤维进行了鉴别。结果表明:PHBV/PLA共混纤维的燃烧特征及显微镜下观察的表观和截面形态与常见的合成纤维的特征相似,燃烧特征的具体表现为靠近火焰时熔缩,接触火焰时有熔滴现象且冒白烟,离开火焰时继续燃烧,燃烧时具有特异气味,残留物呈黑色硬块状; PHBV/PLA共混纤维的横截面形态为近似圆形或略呈多边形,纵面形态为表面光滑或略有不平整,未见较深沟槽;使用燃烧法和显微镜法,能够较易将PHBV/PLA共混纤维和棉、毛等天然纤维、粘胶纤维等再生纤维素纤维相区别;PHBV/PLA共混纤维在常温下溶于98%硫酸、二氯甲烷,70℃下溶于甲酸/氯化锌溶液,通过溶解法,可将PHBV/PLA共混纤维和涤纶、锦纶、腈纶、丙纶等常见合成纤维相区别;PHBV/PLA共混纤维在1 722 cm~(-1)和1 748 cm~(-1)处出现了双吸收峰,PLA纤维仅在1 748 cm~(-1)处出现了吸收峰,均属于酯基中羰基的伸缩振动吸收峰,二者的红外光谱存在显著差异。     

PLA/PHBV纤维的热学性能

对聚乳酸/聚(3-羟基丁酸酯-co-3-羟基戊酸酯)(PLA/PHBV)纤维进行了热失重分析、差示扫描量热分析、热收缩测试及燃烧性能测试。结果表明:PLA/PHBV纤维的起始分解温度为232℃左右,体现出较好的热稳定性;PLA/PHBV纤维的DSC曲线有两个熔融峰,PLA组分的熔融峰温度为149℃,PHBV组分的熔融峰温度为161.8℃;PLA/PHBV纤维的沸水收缩率为7.5%,表现出了良好的热收缩性能;PLA/PHBV纤维表现出优异的阻燃性能。     

PLA/PHBV纤维的基本力学性能研究

对PLA/PHBV纤维进行了干湿断裂强力、一次定拉伸弹性、循环定拉伸弹性及松弛试验,并与纯PLA纤维进行对比来探究PLA/PHBV纤维的基本力学性能。结果表明:PLA/PHBV纤维的断裂强力和断裂伸长率较小,延展性一般,属于硬而脆的纤维;在较大形变下复合纤维表现出良好的弹性回复能力,并在经过反复拉伸后仍具备优良的弹性回复能力;相较于PLA纤维,PLA/PHBV纤维表现出良好的抗疲劳性。     

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。     

PHBV/PCL共混纤维的结构与性能

采用熔融纺丝法制备聚羟基丁酸戊酸酯(PHBV)/聚ε-己内酯(PCL)生物可降解共混纤维。采用差示扫描量热仪、广角X射线衍射仪、热台偏光显微镜和傅立叶变换红外光谱仪对PHBV/PCL共混体系的相容性和结晶性能进行了表征。结果表明:PHBV和PCL是不相容的;PHBV/PCL共混体系中的PHBV影响了PCL的结晶机制和结晶速率,PCL的结晶形态没有改变;PCL不影响PHBV的结晶机制,降低了PHBV的结晶速率,改变了PHBV的结晶形态。     

PLA/PHBV共混改性研究

采用熔融共混法制备了聚乳酸/聚(3-羟基丁酸-co-3-羟基戊酸酯)(PLA/PHBV)共混物,研究了PLA/PHBV质量比以及滑石粉(Talc)含量对PLA/PHBV共混物性能的影响。结果表明,随着PHBV含量的增加,PLA/PHBV的结晶度先降低后升高,断裂伸长率提高了21.81%,冲击强度提高了35.9%,拉伸强度下降;随着Talc含量的增加,PLA/PHBV/Talc的结晶度增大,冲击强度提高了12.4%,但是断裂伸长率和拉伸强度有所下降;在不显著降低拉伸强度和弯曲强度的前提下,PHBV的含量为20%(质量分数,下同)且Talc含量为1.5%时,复合材料的力学性能最优。     

PLA/PHBV共混3D打印线材的制备及性能研究

采用熔融共混法制备了聚乳酸/聚(3-羟基丁酸-co-3-羟基戊酸酯)(PLA/PHBV)共混物,用熔融沉积成型(FDM)技术制备了三维(3D)打印标准测试样条,研究了PLA/PHBV质量比对PLA/PHBV共混物及3D打印线材性能的影响。结果表明,PLA/PHBV共混材料是完全不相容的体系,随着PHBV含量的增加,PLA/PHBV共混物以及3D打印制品的拉伸强度下降,但断裂伸长率有所提高;弯曲强度及冲击强度均先上升后下降;注塑样品的拉伸强度最大可达43.31 MPa,断裂伸长率可达5.37%;3D打印制品的拉伸强度最大可达49.16 MPa,断裂伸长率可达7.41%;PLA/PHBV共混物以及3D打印制品淬断断面呈现典型的"海岛"分布,PHBV相均匀的分散在PLA基中;随着PHBV含量的增加,注塑样条的断面逐渐变得粗糙,打印制品层与层之间空隙减小,填充率上升,黏结性能提高。     

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。     

PHBV共混改性研究进展

介绍了聚(β-羟基丁酸戊酸酯)(PHBV)的现有生产状况、性能特点以及存在的不足。简述了PHBV结晶改性的研究成果,总结了PHBV共混改性的研究进展,包括PHBV与聚乳酸(PLA)、聚己内酯(PCL)、聚己二酸/对苯二甲酸丁二醇酯(PBAT)、二氧化碳共聚物(PPC)、淀粉、纤维素及有机黏土等。     

静电纺丝法制备PHBV有序纤维

利用静电纺丝转轴法制备羟基丁酸-羟基戊酸共聚酯(PHBV)有序纤维,研究了转轴表面线速度对PHBV纤维结构与性能的影响.结果表明:随着转轴表面线速度的提高,PHBV纤维的排列有序度、晶区取向度及分子链取向度、结晶度以及力学性能提高,10.5m/s时均达到最大值,其后又有所降低;转轴的卷绕对纤维具有拉伸作用,随着转轴表面...     

Dynamic mechanical thermal analysis of biocomposites based on PLA and PHBV—A comparative study to PP counterparts

The primary objective of this study was the investigation of thermo‐mechanical behavior of cellulosic fiber reinforced polylactid (PLA) and poly(3‐hydroxybutyrate‐co‐3‐hydroxyvalerate) (PHBV) biopolymers. Both PLA and PHBV were processed with 30 wt % of cellulosic fibers; moreover, to improve the processability and mechanical performance, PHBV was previously blended with 30% by weight poly(butylene adipate‐co‐butylene terephthalate) (PBAT). Secondary target was the comparison of the obtained results to natural fiber reinforced polypropylene (PP) composites reinforced with exact the same fibers and processed by using identical techniques. For validation the thermo‐mechanical properties, a dynamic mechanical thermal analysis (DMTA) was applied. Storage modulus (E′), loss modulus (E″), and loss factor (tan δ) were determined. The DMTA results indicate decreased polymer chain motion with resulting improvement of stiffness expressed by the storage modulus. Finally, the effectiveness of fiber on the moduli was investigated. The C coefficient differs in dependence on fiber type, use of coupling agent, and the reference temperature in glassy state. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 3175–3183, 2013     

Development,optimization, and characterization of electrospun poly(lactic acid) nanofibers containing multi‐walled carbon nanotubes

Electrospinning of poly (L ‐D ‐lactic acid) (PLA) was investigated with the addition of multi‐walled carbon nanotubes (MWNT) for development of a scaffold for tissue engineering. Through this experiment, it was determined that the optimal concentration of PLA with weight average molecular weight (M_w) 250,000 g/mol is ～20 wt % as indicated by scanning electron microscopy. This concentration produces fibers with no beading or film formation. The preferred solvent system is a combination of chloroform and dimethyl formamide to alleviate the volatile action of chloroform. The optimum processing parameters for PLA are an electric field of 1 kV/cm which was determined by a surface response plot to minimize fiber diameter based on the applied voltage, working distance, and addition of MWNT. Fourier Transform infrared spectroscopy has indicated the removal of the solvent system. With the addition of MWNT, the fiber diameter was drastically reduced by 70% to form fibers with a mean diameter of 700 nm. This is believed to be due to an increased surface charge density for the MWNT/polymer solution. Transmission electron microscopy validated the alignment of the MWNT within the fibers. MWNT loading exhibited an increase in the conductance of the scaffold and the tensile modulus at an optimal loading level of 0.25 wt %. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Morphology and thermal degradation studies of melt‐mixed PLA/PHBV biodegradable polymer blend nanocomposites with TiO2 as filler

The morphology and thermal stability of melt‐mixed poly(lactic acid) (PLA)/poly(hydroxybutyrate‐co‐valerate) (PHBV) blends and nanocomposites with small amounts of TiO₂ nanoparticles were investigated. PLA/PHBV at 50/50 w/w formed a co‐continuous structure, and most of the TiO₂ nanoparticles were well dispersed in the PLA phase and on the interface between PLA and PHBV, with a small number of large agglomerates in the PHBV phase. Thermogravimetric analysis (TGA) and TGA–Fourier‐transform infrared spectroscopy was used to study the thermal stability and degradation behavior of the two polymers, their blends, and nanocomposites. The thermal stability of PHBV was improved through blending with PLA, whereas that of the PLA was reduced through blending with PHBV, and the presence of TiO₂ nanoparticles seemingly improved the thermal stability of both polymers in the blend. However, the degradation kinetics results revealed that the nanoparticles could catalyze the degradation process and/or retard the volatilization of the degradation products, depending on their localization and their interaction with the polymer in question. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42138.     

Preparation of porous electro‐spun UPM fibers via photocrosslinking

In this study, a new method of preparing porous ultra‐fine fibers via photocrosslinking was developed. Ultra‐fine unsaturated polyester macromonomor (UPM)/poly(3‐hydroxybutyrate‐co‐3‐hydroxyvalerate) (UPM/ PHBV) blend fibers were electrospun and then the UPM was photocrosslinked by UV irradiation. Different ratios between UPM, PHBV and solvent were tested and the relationship between weight percentage of solutions and diameter of fibers was discussed. Through the test of T_g and T_m we found that UPM and PHBV were immiscible and the phase separation proceeded during the electrospinning. The photocrosslinking time was controlled strictly and the best reaction time can't exceed more than 10 min. After photocrosslinking of UPM, PHBV was extracted from the blend fibers with chloroform. The morphology of the fiber was observed through SEM and fibers were not collapsed during the extracted processing. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

二氧化钛改性PHBV共聚物的成纤性能研究

采用二氧化钛(TiO2)对β-羟基丁酸-co-羟基戊酸共聚物(PHBV)进行共混改性,并进行模拟纺丝。通过测试PHBV/TiO2共混纤维的强度、脆性等基本性能,表明添加TiO2不仅能克服纺程中PH-BV单丝间的粘连,而且有效地提高了纤维的强度,降低了纤维的脆性。通过不同的纺丝条件的探索比较,当PHBV与TiO2共混比例为95:5时,在热水浴成形条件下,能纺丝得到综合性能比较良好的纤维。     

Morphological and mechanical behavior of chemically treated jute‐PHBV bio‐nanocomposites reinforced with silane grafted halloysite nanotubes

In this study, at first, thin films of poly(3‐hydroxybutyrate‐co?3‐hydroxyvalerate) (PHBV) nanocomposites were prepared by adding 1–3 wt % grafted halloysite nanotubes (G‐HNTs). Jute‐PHBV bio‐nanocomposites were then fabricated using these films and chemically treated jute fibers in a compression mold machine. The effect of treatment and modification on jute fiber and halloysite nanotubes (HNTs), and the change in their morphology was investigated using Fourier transform infrared (FTIR) spectroscopy, X‐ray diffraction (XRD), scanning and transmission electron microscopy (SEM, TEM). Flexural and thermomechanical properties were determined using a three‐point bend test and dynamic mechanical analysis (DMA). The results showed separation of fiber bundles with rough fiber surfaces, and grafting of silane coupling agents on fibers and HNTs after the chemical treatment. As a result, a strong bonding was established between the PHBV, G‐HNTs and jute fibers that lead to significant improvements in flexural and thermomechanical properties of jute‐PHBV bio‐nanocomposites. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43994.     

Fabricating novel thermal crosslinked ultrafine fibers via electrospinning

In this article, we report the preparation of a kind of novel crosslinked ultrafine fiber by electrospinning of unsaturated polyester macromonomers (UPM) and subsequent thermal crosslinking. The UPM is prepared via a two‐step reaction with poly(2‐methyl‐1,3‐propyleneadipate) diol terminated (PMPA), isophorone‐diisocyanate (IPDI) and 2‐hydroxyethyl methacrylate (HEMA). Poly(3‐hydroxyl‐butyrate‐co‐3‐hydroxylvalerate) (PHBV) is chosen to improve the processability of the UPM. UPM/PHBV blend ultrafine fibers are successfully electrospun with a proper mass ratio of UPM to PHBV in dichloromethane solution. The fibers are thermally crosslinked after electrospinning. Measurement results indicate that the average diameter of the fibers is about 1 μm and the crosslinked fibers have good solvent‐stability and thermal‐stability. This novel fiber has potential applications in filtration and protective coating. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 107:2142–2149, 2008