扩链剂对PBAT/Talc复合材料性能影响研究

通过熔融共混制备可生物降解的聚对苯二甲酸己二酸丁二醇酯/滑石粉(PBAT/Talc)复合材料,探究滑石粉及扩链剂含量对PBAT/Talc复合材料力学性能、结晶性能、流变性能及微观形貌的影响。结果表明:随着滑石粉及扩链剂含量的增加,复合材料的屈服应力及拉伸模量逐渐增大,但断裂伸长率逐渐下降;当滑石粉及扩链剂含量分别为30%和0.6%时,PBAT/Talc复合材的拉伸强度最高为18.1 MPa,断裂伸长率为257%;随着扩链剂含量的增加,PBAT/Talc复合材料的熔点、结晶度及结晶温度逐渐降低,PBAT/Talc复合材料熔体的拉伸黏度逐渐增大;当扩链剂加入量为0.6%时,滑石粉在PBAT中的分散性最好,未观察到滑石粉团聚现象。     

PGA/PBAT复合材料抗水解性能研究

利用碳化二亚胺类抗水解剂(AHA)与环氧类(ADR)及异氰酸酯类(MDI)扩链剂对聚乙醇酸/聚己二酸-对苯二甲酸丁二醇酯(PGA/PBAT)进行反应挤出改性,分别研究抗水解剂含量与抗水解剂/扩链剂协同作用对PGA/PBAT(GB)复合材料的抗水解性能的影响。结果表明:当AHA/MDI协同使用时,PGA/PBAT复合材料的界面相容性和抗水解性均得到改善,其中GB/AHA(1.0份)/MDI(GBA1.0/MDI)样品的初始拉伸强度可达21.0 MPa,较GB/AHA(0)(GBA0)样品提高35%。在湿热老化环境中,GBA1.0/MDI的力学性能较GBA0更稳定,50%的力学性能保持时间高于24 d,较GBA0提高60%。     

扩链聚对苯二甲酸丁二醇-co-聚己二酸丁二醇酯的合成及表征

采用1,4-丁二醇,对苯二甲酸二甲酯,己二酸合成了聚对苯二甲酸丁二醇-co-聚己二酸丁二醇酯(PBAT)。采用六亚甲基二异氰酸酯作为扩链剂合成了高分子质量的PBAT。研究了扩链反应时间,扩链剂用量对特性黏度的影响;反应温度,扩链剂用量,扩链反应时间对PBAT分子质量、端羧基值的影响。采用核磁共振及红外光谱对聚合物的结构进行了表征。研究结果表明六亚甲基二异氰酸酯可以显著提高PBAT的分子质量,扩链以后力学性能有明显的提高。     

扩链剂增容PLA/PBAT共混物流变性能

通过熔融共混法制备了Joncryl ADR 4370F扩链剂增容聚乳酸/聚对苯二甲酸/己二酸丁二酯(PLA/PBAT)共混物,采用旋转流变仪分别研究了扩链剂和PBAT含量对PLA/PBAT共混物动态流变行为的影响.通过动态应变扫描确定了PLA/PBAT共混物的线性黏弹区,应变选取1％;PLA/PBAT共混物的储能模量和...     

回收PET的反应挤出扩链

在回收的废弃聚对苯二甲酸乙二醇酯(PET)瓶片中添加不同质量分数的均苯四甲酸二酐（PMDA）和环氧树脂作为扩链剂,利用反应挤出技术在同向双螺杆挤出机中反应,分析测试反应产物的特性黏度、端羧基的质量摩尔浓度及结晶性能。结果表明： PMDA和环氧树脂均对PET有一定的扩链作用,且二者合用时扩链效果更佳,反应后PET的特性黏度由0.45 dL/g提高到0.58 dL/g,摩尔质量也显著提高;其中单独使用环氧树脂作为扩链剂时,可以使反应后的PET端羧基含量显著下降,结晶度有所提高。     

多元环氧扩链剂对PLA增强PBAT性能的影响

利用硬质聚乳酸(PLA)对聚对苯二甲酸–己二酸–丁二酯(PBAT)进行增强改性,并加入多元环氧扩链剂苯乙烯–甲基丙烯酸缩水甘油酯共聚物(ADR)对共混物进行原位增容,采用熔融共混法制备PBAT/PLA共混物,通过转矩流变测试、高压毛细管流变测试、拉伸性能测试及扫描电子显微镜观察考察了ADR对共混物加工热稳性能、流变行为、拉伸性能以及微观结构的影响。结果表明,ADR不但起到扩链和增黏作用,提高共混物的加工热稳性,同时起到原位增容作用,在保持PLA增强效应的同时,显著提高共混物的拉伸韧性。当ADR添加量在0.3~0.5份时,共混物具有较优的综合性能。     

双噁唑啉类扩链剂增黏回收的PET的研究

从扩链剂用量、反应时间分别研究了2,2一双（2-噁唑啉）（BOZ）与2,2-（1,3-苯撑）-双（2-噁唑啉）（PBO）对回收的聚对苯二甲酸乙二醇酯（PET）的扩链效果。结果表明：扩链剂量为理论量的3倍,反应时间为4～6rain时获得最大扩链效果。其中BOZ对PET特性黏数的提高效果较好,从0．61提高到0．80。利用红外差减光谱分析了BOZ与PET的扩链反应前后的结构变化,酰胺基团出现以及酯基增加、羧基减少证实了扩链反应的发生;而五元环的存在则表明反应过程是分两步进行的。利用差示扫描量热分析仪分析了残余扩链剂对产物热性能的影响;当扩链剂的添加量较低时,熔融过程中产物的相对分子质量进一步提高,结晶度下降;而当扩链剂添加量较高时,相对分子质量反而下降,结晶度上升。     

环氧扩链剂增容PLA/竹纤维共混物制备与表征

以环氧扩链剂ADR4368为增容改性剂,十八烷基二甲基叔胺为催化剂,利用双螺杆挤出机制备出了一系列聚乳酸(PLA)/竹纤维/ADR共混物,探究了环氧扩链剂对共混物性能的影响。结果表明:环氧扩链剂能够对PLA和竹纤维起到增容作用,共混物的流动性能和结晶度随着ADR用量的增加不断下降,而冷结晶温度则随之升高。微观形貌表明,ADR的引入使竹纤维与PLA两相间黏合能力提高,共混物的孔洞变少。共混物的力学性能随着ADR的引入而得到提升,且当ADR用量相对于竹纤维为0.5%,催化剂用量为0.1%时效果最好,此时拉伸强度是PLA/竹纤维共混物的1.21倍,断裂伸长率则是其1.6倍,即环氧扩链剂能够起到增容PLA与竹纤维的作用。     

扩链剂ADR对PLA/Nano-ZnO/CCA纳米复合抗菌材料的影响

将环氧系扩链剂ADR添加到聚乳酸(PLA)/Nano-ZnO/叶绿素铜酸(CCA)纳米复合抗菌材料中,研究了ADR添加量对复合材料抗菌性能和力学性能的影响。结果表明,在ADR质量分数为0%~1.0%范围内,随ADR含量的增多,复合材料对大肠杆菌的抗菌性能略有减弱,其缺口冲击强度有较大幅度的增加,弯曲强度、拉伸强度略有增加,断裂伸长率先增大后减小,ADR质量分数小于1.0%时仍属强抗菌材料。当ADR质量分数为1.0%时复合材料的综合性能较好,其抗菌率为99.4%,拉伸强度、断裂伸长率、缺口冲击强度、弯曲强度分别比PLA/Nano-ZnO/CCA复合材料提高了4.6%,11.6倍、71.4%,4.8%。     

聚己二酸丁二醇-co-聚对苯二甲酸丁二醇酯扩链改性研究

为了降低聚己二酸丁二醇-co-聚对苯二甲酸丁二醇酯(PBAT)的熔融指数,在双螺杆中,利用多元环氧扩链剂(ADR)对PBAT进行了扩链反应.基于正交实验对ADR扩链PBAT反应进行了研究,确定了影响反应的主要因素,并对扩链后的树脂进行了流变以及常规性能研究.结果 表明,扩链剂浓度对扩链反应速率影响最大,反应温度次之.A...     

Effect of chain extrender on the compatibility,mechanical and gas barrier properties of poly(butylene adipate-co-terephthalate)/poly(propylene carbonate) bio-composites

Bio-composites consisting of poly(butylene adipate-co-terephthalate) (PBAT), poly(propylene carbonate) (PPC) and epoxy chain extender ADR 4468 were fabricated via melt blending using a torque rheometer. The relationship of the torque, melt viscosity, and molecular weight of the bio-composites was established via polymeric liquid theory to estimate the real-time chain extension reaction rate under different ADR contents. At the meantime, rheological behavior, thermal and mechanical properties, morphologies, gas barrier properties of the PBAT/PPC/ADR bio-composites were systematically characterized. The corresponding results revealed that the water vapor transmission rate (WVTR) reduced by 50% under 30 phr (parts per hundreds of resin) PPC content. The addition of ADR is beneficial to improve the mechanical properties, thermal stability and phase dispersion of PBAT/PPC without affecting the water barrier property. With 3 phr ADR, the tensile stress and elongation at break were increased from 19.5 MPa and 1184% to 26.9 MPa and 1443%, respectively. In addition, the data of the torque rheometer revealed that the chain extension reaction rate and the melt viscosity was increased with the increasing ADR content, but the reaction rate was reduced with the excessive viscosity.     

Fabrication and Properties of Modified Poly(butylene terephthalate) with Two-Step Chain Extension

High-viscosity, low-crosslinked poly(butylene terephthalate) (PBT) from organic chain extenders and inorganic particles are prepared. PBT modification adopted from multifunctional, commercially available chain extension containing nine epoxy groups (ADR9) occurs in the first-step chain extension; hydroxyl addition modified dioxazoline (BOZ) serves as the second step. Anion stratiform inorganic hydrotalcite (HT) is used to adjust the crystallization behavior and damp-heat aging properties of PBT. The reaction between the chain extender and PBT end-groups such as carboxyl (–COOH) and hydroxyl (–OH) enhances the interfacial bonding between the PBT matrix and dispersed HT phases. With a fraction of chain extenders in the PBT matrix, the chain-extended PBT exhibits higher mechanical properties, intrinsic viscosity, average molecular weight, and melt viscosity than those of unmodified PBT. Damp-heat aging resistance measurements show correlation with initial carboxyl content in the resin. Reducing the concentration of carboxyl end-groups in the resin is shown to increase hydrolytic stability. The modified PBT resin can be used in optical fiber communication cable industry for its high level of damp-heat aging resistance as well as good mechanic properties.     

Understanding the effect of chain extender on poly(butylene adipate-co-terephthalate) structure

We investigated poly(butylene adipate-co-terephthalate) (PBAT), a biodegradable polymer, under the influence of a chain extender (a multifunctional epoxide oligomer, Joncryl ADR-4370S^®, ADR) at different concentrations, and correlated their properties concerning the molecular interaction between the active sites of the structures. Several studies have used ADR in poly(lactic acid)-PBAT blends; however, the effect of ADR in terms of chemical and physical interaction with PBAT is not investigated in-depth, which can limit its applications. The chain extender is usually applied to improve the mechanical and thermal properties and PBAT resistance to thermal degradation. The developed materials were evaluated by high-resolution solid-state nuclear magnetic resonance (NMR), Fourier transform infrared spectroscopy (FTIR), mechanical and thermal properties, and rheological measurements. NMR and FTIR indicate an interaction between the carboxylic sites of PBAT and the epoxy sites of ADR. PBAT-2%ADR shows higher tensile properties, probably due to the hydrogen bonds and interactions of π–π nature between the materials; in this case, the ADR can act as a reinforcing agent. High contents of chain extender can change the nature of the interaction and influence the final properties of the polymer. The effect of this additive was found to be strongly dependent on the content used and the polymer processing. It was observed that ADR could act as an internal lubricant during processing (due to the low molecular weight of this additive), demonstrating the importance of processing parameters control.

     

Hydrophobic nanocomposites of PBAT with Cl-fn-POSS nanofiller as compostable food packaging films

Antibacterial nanocomposite films of poly(butylene adipate-co-terephthalate) (PBAT) incorporated with different weight percentage of octakis(3-chloropropyl)octasilsesquioxane (chloropropyl functionalized POSS [Cl-fn-POSS]) nanofiller were prepared. The mechanical, thermal, morphological, barrier, and antimicrobial properties were examined. The mechanical properties of the nanocomposite films were enhanced by the addition of Cl-fn-POSS nanofiller. An optimum filler loading of 3 wt% is identified to be best suited for maximum enhancement in tensile strength (24 MPa for 3 wt% filled PBAT vs 11 MPa for neat PBAT) while a 1 wt% filler loading was adequate to double the tensile strength. The barrier properties (WVTR and oxygen transmission rate) of PBAT was improved by the presence of Cl-fn-POSS. A volume of 3 wt% filler loading results in 50% reduction of water permeation and 10% reduction in oxygen transmission. The thermogravimetric analyses of the nanocomposites indicated that the filler enabled the enhancement of thermal stability of PBAT. The nanocomposite films revealed antimicrobial activity with this activity increasing with increasing filler content. PBAT is compostable under suitable conditions and with a low weight percentage of filler that is largely made of silicon dioxide these nanocomposite films can find application as biodegradable food packaging material given their flexibility.     

Biodegradable blends of poly(butylene adipate-co-terephthalate) and polyglycolic acid with enhanced mechanical,rheological and barrier performances

Blends of poly(butylene adipate-co-terephthalate)/polyglycolic acid (PBAT/PGA) were prepared by melt blending, in which PGA was used as reinforcing component. Impacts of PGA content on tensile property, microstructure, crystallization property, melt viscosity, barrier performance of the blends were researched. Compared with very soft behavior of PBAT, the tensile yield strength and modulus of PBAT/PGA (65/35) sample increased from 7.67, 62.6 MPa of neat PBAT to 12.05, 158.9 MPa, respectively. However, owing to poor PBAT/PGA interface compatibility, its elongation at break decreased significantly from 1082.1% to 88.7%. An epoxy chain extender (ADR) was used as reactive modifier to improve its interface compatibility and rheological property. The related physical properties of PBAT/PGA/ADR (65/35/x) samples with various ADR contents were evaluated in detail. It was found that ADR exerted relatively complex influences on the properties. Overall, compared with neat PBAT and PBAT/PGA (65/35) sample, the PBAT/PGA/ADR (65/35/x) samples exhibited better stiffness-ductility balance and higher processing stability.     

偶联剂对PLA/PBAT/WF复合材料3D打印性能的影响

以聚乳酸（PLA）和聚己二酸/对苯二甲酸丁二酯（PBAT）为基体,杨木粉（WF）为填充增强材料,使用混炼机熔融共混制备PLA/PBAT/WF复合材料,采用熔融沉积成型（FDM）技术制备标准实验试样,通过扫描电子显微镜、红外光谱分析、旋转流变测试以及力学试验等方法,研究不同含量的硅烷偶联剂KH550对PLA/PBAT共混物以及PLA/PBAT/WF的相容性、流变性及力学性能的影响。结果表明,在偶联剂用量为3 %（质量分数,下同）时,拉伸强度提高了136 %;偶联剂KH550与 PLA和PBAT共价键偶联生成接枝聚合物,二者相容性得到提高;同时偶联剂与WF表面羟基发生缩聚反应有效的改善了其与PLA/PBAT的基体相容性,PLA/PBAT/WF复合材料的FDM的制件力学性能得到较大提升;复合材料的黏度随偶联剂含量的增加呈下降的趋势,含量为3 %时线材的综合打印性能及制品质量最佳。     

熔融扩链反应制备PLA／PBAT多嵌段共聚物

以六亚甲基二异氰酸酯(HDI)为扩链剂,在催化剂辛酸亚锡作用下,通过熔融扩链反应制备了聚乳酸(PLA)/聚(己二酸丁二酯/对苯二甲酸丁二酯)(PBAT)多嵌段共聚物.研究了反应时间、温度、扩链剂用量等工艺条件对PLA/PBAT共聚物结构、相对分子质量的影响.用红外光谱仪、核磁共振仪、偏光显微镜等分析手段对PLA、PBAT和PLA/PBAT共聚物进行了分析表征.结果表明,通过扩链反应,PLA的分子链中引入了新的嵌段,其相时分子质量及柔韧性大幅度提高.     

Molecular and structural analysis of epoxide‐modified recycled poly(ethylene terephthalate) from rheological data

A multifunctional epoxide chain extender (ADR4370S) was used to increase the molecular weight of recycled poly(ethylene terephthalate) (R‐PET). The extension processing was carried out by melt mixing reaction. The effects of ADR4370S content on the molecular structure [molecular weight, molecular weight distributions (MWDs), branching, and gel‐like structures] of modified R‐PET were rheologically investigated. The results showed that the complex and apparent viscosity of the modified R‐PET were larger than those of unmodified one. The solid‐like behavior of R‐PET was enhanced after the reactive modification. The increments of balancing torque, reaction peak, and shear‐thinning behavior became more pronounced by increasing the concentration of ADR4370S. Reactive modification was characterized by the presence of long‐chain branching resulted in a wider MWD. Modified Cole–Cole plots demonstrated a shift toward higher storage modulus values at a given loss modulus value for the modified R‐PET samples. High concentration of ADR4370S (>1.5 wt%) resulted in a polymeric structure near the sol–gel transition point whose linear viscoelastic properties obeyed scaling law. The relaxation time was prolonged with the amount of ADR4370S increase. The decrease in the melt point and crystallization temperature of the modified R‐PET was correlated to the presence of chain branching. POLYM. ENG. SCI., 2012. © 2012 Society of Plastics Engineers     

Improved properties of poly(butylene adipate-co-terephthalate)/calcium carbonate films through silane modification

One of the most used inorganic fillers is calcium carbonate which quite efficiently enhances the mechanical characteristics while simultaneously lower the cost of thermoplastics, particularly for biodegradable polyester. Virtually, all studies so far have focused on the quest for the filling and modification of nano-sized calcium carbonates. However, the quantity of nano-sized CaCO₃ added in the polymer is usually lower than 10%, owing to its high-surface energy and high-surface area and makes powder easier to agglomerate. In this work, we prepared poly(butylene adipate-co-terephthalate) (PBAT)/calcium carbonate composite films by extrusion-blown films with up to 40 wt% micro-sized CaCO₃ content. The influence of particle size (5–12 μm) and modification of the particles (with and without silane coupling agents) on the rheological and mechanical properties was thoroughly investigated. Of all the particle sizes employed in this study, the 5 μm (3000 mesh) particles with 30 wt% content coated with 2 wt% aliphatic silane coupling (CA1) agent was observed to furnish the optimum combination of characteristics. The mechanical properties of P7C3/CA1-2 film even better than that of neat PBAT film. These results provided a simple approach for PBAT/CaCO₃ films manufacture with low-cost and simultaneously with sound mechanical properties, which can be good candidate for mulching films and packaging applications.     

尼龙6化学扩链

用挤出机熔融共混法,以双２口恶唑啉和双酰基双内酰胺化合物为扩链剂,对ＰＡ６进行化学扩链,使ＰＡ６的分子量由１６．７ｋｇ／ｍｏｌ提高到２１．０ｋｇ／ｍｏｌ,偶联效率最高可达７０％;同时考查了扩链剂用量、铜盐、共混温度与时间以及后热处理对扩链效果的影响。