聚丁二酸丁二醇酯的扩链改性及共混研究

采用扩链剂2,4-甲苯二异氰酸酯（TDI）、2,2′-双（2-恶唑啉）（BOZ）以及新型扩链剂ADR-4370对聚丁二酸丁二醇酯（PBS）进行扩链,对比研究3种扩链剂对PBS性能的影响。采用聚乳酸（PLA）与PBS共混,选择最佳配比以及合适的共混工艺。结果表明,新型扩链剂ADR-4370可以良好的改善PBS的加工性能和机械性能,m（PBS）/m（PLA）最佳配比为70：30,在共混同时进行扩链比扩链后再共混可以更好的提高PBS/PLA的性能。     

增容剂种类对熔融共混法制备PLA/PBAT体系的影响

采用熔融共混法制备了不同增容剂体系的聚乳酸/聚己二酸-对苯二甲酸-丁二酯共聚物(PLA/PBAT)共混熔体,系统地研究了采用扩链剂SW04、环氧扩链剂XY-4370以及扩链剂Joncryl作为增容剂改性的PLA/PBAT体系。并对他们的熔体流动速率、力学性能以及热性能进行检测。对比实际挤出实验过程中熔体的情况,使用扩链剂Joncryl作为增容剂的体系熔体更均匀,明显改善挤出胀大现象,对PLA/PBAT体系的增容效果更好。且使用扩链剂Joncryl作为增容剂的熔体稳定性更好,综合力学性能也更佳。     

扩链剂改性聚乳酸性能

通过熔融共混方法,采用ADR-4368扩链剂对聚乳酸(PLA)进行改性研究,研究扩链剂的加入量对PLA力学性能、熔体流动速率(MFR)、DSC、TG、熔体强度的影响。结果表明:扩链剂的加入提高了PLA的拉伸强度、弯曲强度、热稳定性能,熔融温度以及熔体强度,随着扩链剂质量分数的增加,PLA的拉伸强度及热稳定性逐渐提高;扩链剂的加入使PLA的熔体流动速率、冷结晶温度和结晶度下降。     

聚丁二酸丁二醇酯扩链及其发泡行为的研究

以聚丁二酸丁二醇酯(PBS)为基体,ADR-4370S为扩链剂,通过熔融共混法制备了扩链PBS;通过扭矩曲线、凝胶含量测试、差示扫描量热仪测试、旋转流变仪测试,研究了PBS扩链前后分子结构、热性能、流变性能的变化;利用超临界二氧化碳(CO_2)作为物理发泡剂,通过间歇式釜压发泡成型制得不同类型的PBS泡沫样品,研究了扩链剂添加量和发泡温度对PBS发泡行为的影响。结果表明,随着扩链剂的加入,PBS的分子链由线形转变为长支化结构,甚至形成了部分交联网状结构;PBS的结晶温度和黏弹性逐渐提高;当扩链剂添加量为1.5份(质量份,下同),发泡温度为105℃时,PBS的发泡倍率取得最大值。     

PBAT/PLA共混物的热力学性能和结晶性能的研究

利用熔融共混制备己二酸丁二醇酯-对苯二甲酸丁二醇酯共聚物(PBAT)/聚乳酸(PLA)共混物,采用Joncryl~? ADR-4368对共混体系进行改性,通过差示扫描量热法研究了共混比例和扩链剂的加入对该共混体系的热力学性能的影响,通过小角激光光散射和广角X射线衍射研究了共混比例和扩链剂的加入对该体系的结晶行为的影响,利用Elmendorf撕裂和拉伸测试分析该共混体系的力学性能。结果表明,共混之后PLA和扩链剂对PBAT有着成核作用。PBAT/PLA共混体系中PLA的冷结晶温度显著下降,PLA含量为20%时扩链剂的加入最终使得PLA的冷结晶消失。扩链剂的加入提高了PBAT的结晶能力,但未改变其晶型。PBAT/PLA共混后力学性能显著改善,且扩链剂的加入使得断裂伸长率提高约一倍。     

用于3D打印的改性聚乳酸丝材的制备与研究

以聚乳酸(PLA)为基材,Joncryl ADR 4370S为扩链剂,采用熔融共混工艺制备了改性PLA,并通过熔融挤出制得用于3D打印的PLA丝材。研究了ADR扩链剂对PLA热性能、熔体强度、力学性能的影响。结果表明,ADR扩链剂提高了PLA的耐热性和熔体强度;相比纯PLA,改性PLA的力学性能有所提高,当ADR用量为0.4%时,改性PLA的力学性能最佳。采用熔融沉积成型桌面3D打印机测试了PLA丝材的打印效果,结果表明,ADR用量为0.4%时,改性PLA丝材的综合打印性能最好。     

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损耗模量随着角频率的增加而增大,但复数黏度却降低,共混物熔体呈现剪切变稀行为,是典型的假塑性流体流动特征;随着扩链剂和PBAT含量的增加,共混物的储能模量、损耗模量和复数黏度增大;Han曲线分析表明,扩链剂的加入改善了共混物的相容性;动态时间扫描表明,时间对纯PLA和PBAT的储能模量基本没有影响,PLA/PBAT共混物的储能模量随时间的延长而降低,扩链剂和PBAT含量不同,使得时间对共混物储能模量的影响不同。     

聚乳酸/聚乙醇酸共混合金界面改性研究

用熔融共混挤出法制备了不同配比的聚乳酸(PLA)/聚乙醇酸(PGA)共混合金,并分别加入环氧型扩链剂ADR 4370F进行对比分析,通过拉伸性能测试、弯曲性能测试、缺口冲击强度测试、扫描电子显微镜(SEM)和差示扫描量热(DSC)仪研究了共混合金力学性能、相容性和结晶性能。结果表明:与纯PLA和纯PGA相比,PLA/PGA共混合金的相容性差,导致力学性能降低,纯PLA、纯PGA和70%PLA/30%PGA合金的拉伸强度、弯曲强度、断裂伸长率和缺口冲击强度分别为58.6 MPa,123.5 MPa,8.52%,9.0 J/m;91.9 MPa,157.6 MPa,7.9%,5.2 J/m;41.2 MPa,91.2 MPa,3.8%,2.0 J/m。PLA和PGA可以互相加快结晶速度,加入环氧型扩链剂可以改善合金的相容性,上述四个力学性能可相应提高到49.2 MPa,96.0 MPa,4.5%,4.3 J/m,而且降低了PLA和PGA的结晶度。另外,向PLA中加入1%PGA时,PGA可以充当PLA的成核剂,使PLA的冷结晶温度降低10℃左右,结晶度提高1.3%。     

通过热处理评价PLA及改性PLA的结晶性能

采用一种环氧类大分子扩链剂(聚甲基丙烯酸甲酯-co-甲基丙烯酸环氧丙酯)与聚乳酸(PLA)进行共混,考察了扩链剂用量对PLA摩尔质量的影响,以及热处理温度和时间、扩链剂用量对共混物热力学行为和结晶行为的影响。结果表明:随着扩链剂用量的增加,PLA的摩尔质量显著提高;正常降温的PLA及其共混物内部没有结晶,热处理可以使PLA及其共混物结晶,热处理温度越高,保温时间越长,结晶度越高;选择合适的条件进行热处理可以以样品的结晶程度评价不同PLA样品的结晶能力,扩链剂的引入使PLA结晶能力下降,选取相同条件进行热处理时,扩链剂含量越大,共混物结晶度越低。     

扩链剂的合成及其在聚乳酸中的应用

采用溶液聚合合成了扩链剂苯乙烯-甲基丙烯酸缩水甘油酯共聚物(KL-E4370),用红外光谱和示差扫描量热仪对KL-E4370的结构和组成进行了表征,并进一步将KL-E4370用于聚乳酸(PLA)扩链,通过转矩流变仪、熔体流动速率测定仪等手段研究了KL-E4370对PLA的流变行为、摩尔质量和熔体流动速率的影响。结果表明,KLE4370的扩链效果明显;当扩链剂的质量分数为0.75%时,PLA的黏均摩尔质量为49 000 g/mol,熔体质量流动速率为0.46 g/10min。     

Effects of the chain‐extender content on the structure and performance of poly(lactic acid)–poly(butylene succinate)–microcrystalline cellulose composites

Composites of poly(lactic acid) (PLA) with poly(butylene succinate) (PBS) and microcrystalline cellulose (MCC) as reinforcements of the polymer matrix were prepared by melt blending to improve the brittleness of PLA. As a reactive compatibilizer, a chain extender was used in an attempt to solve the composites’ interfacial problems and to improve their mechanical properties; Fourier transform infrared spectroscopy indicated that the chain extender functionally reacted with PLA, PBS, and MCC mainly through end carboxyls or end hydroxyls. Scanning electron microscopy indicated that the chain extender significantly improved the cohesive interfacial forces. Differential scanning calorimetry and X‐ray diffraction showed that the chain extender inhibited crystallization, and these effects were greater when its percentage was increased. The addition of chain extender improved the tensile and impact strength of the composites, and this improvement was proportional to the chain‐extender percentage. However, the elongation at break decreased when the chain‐extender percentage was over 0.5% because of mild crosslinking within the resin matrix. Rheology indicated that the complex viscosity and storage and loss moduli of the composites increased with increasing amount of chain extender; this indicated that the addition of chain extender improved the melt strength and processability of the composites. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44895.     

基于异氰酸酯衍生物的聚乳酸熔融扩链工艺、动力学及结构表征

以微波法氧化锌（ZnO）柱撑有机皂石催化丙交酯开环聚合的聚乳酸(PLA)为原料,分别采用二苯基甲烷二异氰酸酯 (MDI)和六亚甲基二异氰酸酯(HDI)进行熔融扩链反应,研究了扩链剂的用量和反应时间对PLA相对分子质量的影响,并对PLA的扩链动力学进行了研究。结果表明,最优的扩链反应工艺参数为：反应温度180 ℃,nNCO：nOH为2.5：1,MDI扩链时间为45 min,HDI扩链时间为30 min;MDI和HDI扩链反应的表观速率常数分别为6.081×10^3、6.98×10^3 g/(mol·min)。     

回收尼龙的扩链改性研究

研究了回收尼龙扩链改性中扩链剂KL-E4370用量、吸酸剂的品种、共混条件对扩链效果的影响。结果显示,扩链剂KL-E4370用量为2%,吸酸剂氧化镁用量为2%,加工温度230℃,主机频率为8Hz下改性效果最好。     

The effect of poly(butylene succinate) content on the structure and thermal and mechanical properties of its blends with polylactide

Poly(butylene succinate) (PBS) and polylactide (PLA) were blended in a co‐rotating twin‐screw extruder with various contents of PBS from 0 to 100 wt%. The effect of PBS content on the thermal and mechanical properties of PBS/PLA blends was investigated by using DSC, softening point measurements, a Charpy impact test and tensile testing. The Fourier transform infrared spectra showed that the polymers are immiscible, but the addition of PBS could modify the PLA structure in PBS/PLA blends by changing the content of amorphous and crystalline phases. In addition, the cold crystallization temperature of PLA in blends decreases in comparison with pure PLA, which shows that PBS could have a plasticizing effect on PLA. This is confirmed by the results of DSC analysis. The mechanical properties of the blends depend on the percentage of PBS addition. Typically, the mechanical properties of PBS/PLA blends are intermediate between the properties of the polyesters from which they are obtained. However, in some cases unexpected changes in mechanical properties of the blends were observed. For example, the elongation at break for a PBS/PLA blend containing 10 wt% PLA is higher than for pure PBS. © 2019 Society of Chemical Industry     

聚乳酸增韧改性研究

通过熔融共混法制备了通用注塑级聚乳酸(PLA)材料,研究了刚性粒子种类,增韧剂种类和协同增韧等对PLA力学性能的影响,同时通过控制扩链剂的添加量有效地对注塑级PLA的熔体流动速率(MFR)进行控制。结果表明:协同增韧剂对PLA有较好的增韧效果,冲击强度从3.5 kJ/m2提高到15 kJ/m2,是单一增韧剂的2.5倍。通过引入扩链剂,得到一系列不同MFR的注塑级PLA材料,满足不同的工业化产品需求。     

聚乳酸/聚丁二酸丁二醇酯共混物的研究

通过熔融共混制备了聚乳酸(PLA)/聚丁二酸丁二醇酯(PBS)共混物,采用扫描电子显微镜、差示扫描量热仪、旋转流变仪对其相容性、热性能和黏度等进行了研究,并研究了PBS的加入对PLA力学性能的影响。结果表明,PLA和PBS之间是部分相容的,PBS的少量添加并不影响PLA的拉伸强度,且其冲击强度随着PBS含量的增加呈先上升后下降的趋势,当PBS含量为10份时,共混物的冲击强度最好;与纯PLA相比,共混物的黏度有所增加,且随着PBS含量的增加,共混物的黏度逐渐增大;PBS的添加起到异相成核作用,促进了PLA的结晶。     

Synergistic toughening and reinforcement of poly(lactic acid) with epoxy-terminated hyperbranched polymers

Poly(lactic acid) (PLA) is an eco-friendly and biodegradable material. However, its molecular chain was rigid and showed limited toughness. In this work, PLA was modified with epoxy-terminated hyperbranched polymer (EHBP) by melt blending to improve the toughness. The results showed that epoxy groups within EHBP reacted with carboxyl and hydroxyl groups of PLA, forming chemical micro-crosslinking. In addition, intermolecular hydrogen bonds were also formed between EHBP and PLA. The combined action of the above two aspects ultimately improved the toughness and strength of PLA. The mechanical property tests results showed that the mechanical properties of PLA improved best when 2.5 phr of EHBP was added. At this point, compared with neat PLA, the maximum tensile strength, impact strength, elongation at break, and flexural modulus of PLA/EHBP increased by 17.4%, 54.5%, 107.1%, and 25.8%, respectively, compared to those of neat PLA. It achieves the goal of simultaneously enhancing the toughness and strength of PLA and subsequently expands its potential application applications.