TBCL的合成及其在尼龙6中的应用

以对苯二甲酰氯和己内酰胺为原料,通过无机碱中和制得目标产物对苯二甲酰双己内酰胺(TBCL),反应过程不产生有机盐废水,反应条件温和。再通过双螺杆挤出机熔融共混制备了TBCL/尼龙6(PA6)共混物。通过红外光谱(FTIR)和差示扫描量热仪(DSC)对TBCL进行结构表征,通过转矩流变仪、万能拉力机与数位冲击仪等考察了TBCL对PA6流变性能、力学性能和热稳定性的影响。结果表明,加入TBCL后,PA6共混物的流动性下降,冲击强度与热变形温度提高。随着添加量的增加,弯曲模量下降幅度不大,但冲击强度则持续提升,基本实现了PA6刚性几乎不损失的情况下韧性显著提高。     

PA6含量对PVC/PA6共混物形态结构与力学性能的影响

以EVA-g-MAH为相容剂,将PVC与自制的低熔点PA6共混制备了PVC/PA6共混物。通过扫描电子显微镜(SEM)和力学性能测试研究了PA6含量对PVC/PA6共混物形态结构及力学性能的影响。SEM分析结果显示:随着PA6含量的增加,PVC/PA6共混物的分散相尺寸逐渐增大,当PA6含量为10%时,共混物中分散相的分散尺寸最小为1μm;当PA6含量为50%时,共混物为两相共连续结构;当PA6含量为60%时,共混物中PA6为连续相,PVC为分散相。力学性能测试结果表明:当PA6含量为10%时,共混物的缺口冲击强度和拉伸强度都较PVC有明显提高,分别提高了约50%与30%,达到了6.29kJ/m2和60MPa。采用差示扫描量热仪(DSC)研究了PVC/PA6共混物的结晶温度,检测结果显示:PVC/PA6共混物呈现非晶结构。     

反应挤出PA6/SEBS原位合金的制备与表征

以己内酰胺和马来酸酐接枝氢化苯乙烯-丁二烯嵌段共聚物(SEBS-g-MA)为原料,通过反应挤出己内酰胺阴离子开环聚合法制备尼龙6(PA6)/氢化苯乙烯-丁二烯嵌段共聚弹性体(SEBS)原位合金。首先研究了SEBS-g-MA对己内酰胺阴离子开环聚合速率及单体转化率的影响,并对原位合金进行了红外光谱、扫描电镜以及力学性能测试。结果表明,合金制备过程中原位生成了SEBS-g-PA6增容物;随着SEBS-g-MA含量的增加,聚合速率延缓,单体含量略有增加;扫描电镜图像发现SEBS-g-PA6起到了很好的增容作用,原位合金的拉伸强度有所减小,断裂伸长率和缺口冲击强度分别是纯PA6的7倍和2.4倍。     

三元共聚半芳香尼龙的低温聚合及其性能研究

采用成盐、预聚合、固相聚合三步法制备高摩尔质量的尼龙6T/6I/66(PA6T/6I/66)三元共聚半芳香尼龙。利用红外光谱法表征其化学结构;通过差示扫描量热法(DSC)、热失重分析(TG)研究其热行为;运用动态力学分析(DMA)确定了聚合物玻璃化转变温度;测试了聚合物的力学性能。结果表明,三元共聚半芳香尼龙的耐热性较PA66有大幅度提高,同时其具有优良的拉伸强度、弯曲强度。     

CaCl_2对PA6结构和力学性能影响

为了研究CaCl_2对PA6结构和力学性能影响,采用双螺杆共混挤出法制备了PA6/CaCl_2复合材料,然后通过傅里叶红外光谱仪(FTIR)、X射线衍射仪(XRD)和差示扫描量热仪(DSC)研究了不同CaCl_2含量对PA6/CaCl_2复合材料结构的影响,并利用毛细管流变仪和电子万能材料试验机对复合材料的流变性能和力学性能进行分析。结果表明:PA6与CaCl_2发生络合作用,随着CaCl_2含量的增加,PA6的结晶温度和熔点逐渐向低温方向偏移,当CaCl_2含量大于6%时,PA6的结晶结构完全变为无定形结构;PA6/CaCl_2熔体的表观黏度随着剪切速率的增加而逐渐减小,属于"切力变稀流体",随着CaCl_2含量的增加,熔体的表观黏度逐渐增大,当CaCl_2含量为8%时,熔体的黏度是纯PA6的6.5倍;拉伸断裂强度和断裂伸长率随着CaCl_2含量的增加而逐渐降低。     

反应性挤出合成PA6/6T及其性能研究

为了得到同时具有优良耐热性能和易加工性能的共聚物PA6/6T,探索了双螺杆反应性挤出预聚物PA6/6T合成较高摩尔质量共聚物PA6/6T的可行性;并通过FTIR、1 H-NMR对最终产物结构进行了表征;利用DSC、TG对其热性能进行了研究;同时研究了其力学性能.结果表明:通过反应性挤出成功得到了具有较高特性黏数的共聚物PA6/6T,通过控制共聚比,可获得熔点低至295℃,拉伸、弯曲和冲击强度分别为72、100 MPa和26 kJ/m2,具有优良综合性能的PA6/6T共聚树脂.     

EBA-g-MAH共聚物增容PA6/ABS共混体系的聚集态结构与性能

通过熔融共混法制备了EBA-g-MAH增容PA6/ABS共混物,采用FTIR、SEM、DSC等测试了EBA-g-MAH对PA6/ABS共混物的增容作用;并讨论了EBA-g-MAH对PA6/ABS共混物的结晶性、力学性能及吸水率的影响。研究结果表明:EBA-g-MAH与PA6发生化学反应所生成的接枝物对PA6/ABS共混物有较好的增容作用,使分散相尺寸明显减小;PA6/ABS共混物的冲击强度得到很大的提高,比纯PA6提高430%,吸水性也得到改善,但是拉伸强度有所降低。DSC研究表明:EBA-g-MAH的加入抑制了PA6/ABS共混物中PA6的结晶,使PA6结晶度降低。     

火焰喷涂聚酰胺12/n-SiO2复合涂层工艺及性能

采用火焰喷涂法制备了聚酰胺12(PA12)及聚酰胺12/纳米SiO2(n-SiO2)复合涂层,并利用电子拉力机、摩擦磨损试验机、红外光谱仪(FTIR)和示差扫描量热仪(DSC)等对涂层的结构与性能进行了研究.红外光谱分析表明PA12及PA12/n-SiO2粉末在火焰喷涂过程中没有发生氧化或降解反应,表明火焰喷涂法适宜制备PA12及PA12/n-SiO2复合涂层;DSC分析结果表明n-SiO2具有成核剂作用,能提高PA12大分子的结晶速度及结晶度;涂层力学性能及摩擦磨损性能分析表明n-SiO2能提高涂层的力学性能,改善涂层的耐老化性能和摩擦磨损性能.当n-SiO2添加量为1.5%(质量)时,涂层综合性能最佳.     

PLA/PA1212共混物结构与力学性能研究

通过熔融共混法制备了不同比例的聚乳酸/尼龙1212(PLA/PA1212)共混物。采用X射线衍射仪(XRD)、差示扫描量热仪(DSC)、傅里叶变换红外光谱仪(FTIR)和万能材料试验机等对共混物结构、热行为和力学性能等进行了表征。XRD和FTIR分析证实PLA和PA1212分子间发生了酯-酰胺交换反应,生成了某种新的结构;DSC结果表明共混材料在升温过程中出现冷结晶和复杂的多重熔融行为;经PA1212改性后,PLA的韧性得到提高,但是拉伸强度有所下降。     

PA11/PA1010共混物的性能研究

采用熔体共混的方法制备了聚酰胺11/聚酰胺1010(PA11/PA1010)共混物,通过力学性能和差示扫描量热(DSC)测试,研究了PA11/PA1010共混物的力学与结晶性能。测试结果表明:PA1010对PA11同时具有增韧、增强作用;当PA11/PA1010为70/30时,共混物开始出现两个结晶峰和低温熔融峰;共混物的结晶和熔融以PA11为主,兼具有PA11和PA1010的优良性能;断裂伸长率、拉伸强度与缺口冲击强度均达到极大值。     

Synthesis of polyamide 6/11 copolymers and their use as matrix polymer in wood‐plastic composites

The goal of this study was to investigate the synthesis and the resulting thermal, rheological, and mechanical properties of polyamide 6/11 copolymers (PA 6/11) as a function of their composition and to further investigate their usability as matrix polymers for wood‐plastic composites (WPC). A significant composition dependency of the melting temperature was found due to the hindered crystallization of the PA 6/11 copolymers with increasing content of the minor component. In result, the lowest melting temperature of the copolymers was measured at 120 °C for 40 wt % of ?‐caprolactam (PA 6/11‐40/60) by DSC analysis. Due to its low melting point and feasible mechanical properties, a copolyamide with 70 wt % of ?‐caprolactam (PA 6/11‐70/30) was chosen as matrix material for the processing of WPC. Incorporation of 30 wt % of wood fibers into PA 6/11‐70/30 caused a significant increase in tensile modulus and a decrease in tensile strength and strain at break. However, the processed WPC still showed an exceptional ductility with a strain at break of 15 to 20%. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 44155.     

Preparation and characterization of high strength and high modulus PVA fiber via dry-wet spinning with cross-linking of boric acid

To improve the mechanical properties of polyvinyl alcohol (PVA) fibers, a series of PVA fibers were prepared via dry-wet spinning with cross-linking of boric acid (BA) (PVA/BA fibers), and using the mixed solvent of dimethyl sulfoxide and water. Moreover, the final PVA/BA fibers were characterized by Fourier transform infrared spectra (FTIR), scanning electron microscopy (SEM), differential scanning calorimetery (DSC), thermogravimetric analyzer (TGA), powder X-ray diffraction (XRD) and yarn strength tester. Furthermore, with the increasing of BA content, FTIR analysis showed that the degree of crosslinking of BA with PVA increased. SEM images of final PVA/BA fibers presented smooth surfaces, and the diameters decreased firstly and then increased. DSC, TGA, and XRD analysis indicated that the melting temperatures, thermal properties and crystallinities first increased and then decreased with the increasing of BA content. In addition, mechanical properties measurements illustrated that the cross-linking existed at an optimal BA content of 0.3 wt%, and PVA/BA-0.3 fiber had the highest tensile strength and Young's modulus of 13.1 ± 0.4 and 360.2 ± 10.4 cN/dtex, respectively.     

浇铸尼龙6/ABS聚合物合金的研究

将丁二烯组分含量不同的丙烯腈-丁二烯-苯乙烯(ABS)加入到单体己内酰胺中,通过阴离子聚合制备浇铸尼龙6(MCPA6)/ABS聚合物合金。采用傅立叶红外光谱、扫描电子显微镜、热重分析以及力学性能测试,研究了ABS的加入对浇铸尼龙6的微观结构、热性能以及力学性能影响。结果表明:ABS通过腈基在己内酰胺的阴离子聚合过程中发生共聚合反应,生成的ABS/MCPA6共聚物对合金两相起到增容作用;合金两相之间相容性随ABS中丁二烯含量的降低有所提高;热稳定性随丁二烯含量的减少而提高,但较MCPA6均有所降低。ABS的加入提高了合金的韧性,其中MCPA6/ABS749S(质量比90/10)较MCPA6缺口冲击强度提高39.73%,但硬度有所下降。     

Effect of the maleation of lignosulfonate on the mechanical and thermal properties of lignosulfonate/poly(ε‐caprolactone) blends

Maleated lignosulfonate (MLS) produced by esterification with maleic anhydride and unmodified lignosulfonate [in the form of lignosulfonic acid (LS)] were incorporated into poly(ε‐caprolactone) (PCL) via melt‐blending. The obtained MLS/PCL composites and LS/PCL composites were characterized by Fourier transform infrared (FTIR) spectroscopy, differential scanning calorimetry (DSC), thermogravimetric (TG) analysis, and electronic universal testing. The FTIR and DSC results show that the interactions between MLS and PCL were stronger than those between LS and PCL, whereas the TG analysis indicated that the LS/PCL composite was more thermally stable than the MLS/PCL composite. The tensile strength of the MLS/PCL blends remained at about 18 MPa when the MLS content reached 50 wt %; this was about 1.7 times larger than that of the LS/PCL blend. The Young's modulus was also enhanced; this indicated an improvement in the mechanical properties. The results show that the maleation of lignosulfonate was beneficial for enhancing the mechanical properties of these blends. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 42925.     

抗氧剂Irganox1010对聚氨酯弹性体老化性能的影响

通过傅里叶红外变换光谱、热分析与力学性能测试,研究了抗氧剂四(3,5-二叔丁基-4-羟基苯丙酸)季戊四醇酯(Irganox1010)对聚氨酯弹性体老化性能的影响。力学测试结果表明,150℃下老化48h后,未加抗氧剂的聚氨酯弹性体的拉伸强度与老化前相比较下降11.6%,而添加抗氧剂的聚氨酯弹性体的拉伸强度与老化前相比较没有下降。热重分析、差示扫描量热分析和红外光谱分析结果表明,抗氧剂Irganox1010能阻碍聚氨酯分子链的断裂,减缓材料的老化,因此能促进聚氨酯弹性体的抗老化性能。     

Structure–property relationships of polycarbonate diol‐based polyurethanes as a function of soft segment content and molar mass

Segmented thermoplastic polyurethanes (PUs) have been synthesized with polycarbonate diol as soft segment and 4,4′‐diphenylmethane diisocyanate and butanediol as hard segment. Two different series employing two different soft‐segment molar mass, 1000 and 2000 g/mol, and by changing the hard‐segment content from 32 to 67% have been investigated with the aim to elucidate the effect of the different content variations on the properties. Morphological, thermal, and mechanical properties have been studied by Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), wide angle X‐ray diffraction, atomic force microscopy, tensile and tear strength, hardness, and specific gravity tests. Properties have been explained from the standpoint of miscibility between hard‐ and soft‐segment microdomains of the tailored segmented PUs through an exhaustive analysis. FTIR, DSC, and DMA measurements revealed that miscibility between hard and soft microdomains increases as the molar mass of the macrodiol decreases. An increase in hard‐segment content entailed the formation of larger hard domains with higher crystallinity what results in superior mechanical properties such as higher tensile stress and tear strength, and hardness. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41704.     

挤出级改性PA6的研究

以高黏尼龙6(PA6)为基体,加入增韧剂、增塑剂,成功制备了低弯曲弹性模量挤出级改性PA6。研究结果表明,在聚乙烯接枝马来酸酐(PE-g-MAH)增韧PA6中,加入增塑剂己内酰胺,大幅改善了PA6的柔顺性。当己内酰胺用量为12.5份、PE-g-MAH用量为12份时,增韧PA6的弯曲强度及弯曲弹性模量分别达到15.3 MPa和600 MPa,而悬臂梁缺口冲击强度高达109.4 k J/m2,从而使增韧PA6保持了一定的刚性,同时还具有橡胶的柔顺性。差示扫描量热分析表明,加入己内酰胺并没有破坏PA6分子内部的氢键,反而增加了PA6分子链段重排的能力,使其规整度进一步增加,当己内酰胺用量从0份增加至10份时,PA6的结晶度从34.21%提高到40.58%。     

Effect of Organomodified Ni-Al Layered Double Hydroxide (OLDH) on the Properties of Polypropylene (PP)/LDH Nanocomposites

This work addresses the effect of organomodified layer double hydroxide (OLDH) on the properties of PP/LDH nanocomposites prepared by melt intercalation method using a single screw extruder with maleic anhydride grafted polypropylene (PP-g-MA) as a compatibilizer. For this, Ni-Al LDH was first prepared by the co-precipitation method at constant pH using their nitrate salts. The above synthesized pristine LDH was organically modified using sodium dodecyl sulphate (SDS) by the regeneration method. The structural and thermal properties of LDH and PP nanocomposites were performed by X-ray diffraction (XRD), FTIR spectroscopy, thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC). The influence of LDH loading on the mechanical and thermal properties of the nanocomposite was also investigated. The XRD results confirmed the formation of exfoliated PP/LDH nanocomposites. PP/LDH nanocomposites exhibited enhanced thermal stability relative to the pure PP. When 10% weight loss was selected as a point of comparison, the decomposition temperature of PP/LDH (5 wt%) nanocomposite was 15.3°C higher than that of pure PP. The DSC result indicated an increase in crystallization and melting temperature of the PP/LDH nanocomposites compared to pure PP. Overall, the mechanical properties of the PP/LDH nanocomposites increased with an increase in the LDH content. The maximum improvement of tensile strength, Young's modulus, flexural strength, and flexural modulus for the PP/LDH nanocomposite was found to be 11, 22.5, 28, and 22%, respectively, over neat PP. For comparison purposes, a nanocomposite with 5 wt% modified bentonite (PP/B5) was also prepared under the same operating condition and there was no significant improvement in mechanical properties (tensile strength and modulus).     

环氧树脂聚酰胺网络体系性能研究

用红外光谱法表征了4种聚酰胺固化剂与环氧树脂按等当量配比,在一定条件下的固化反应过程。DSC法测定了其固化反应活性。桐马聚酰胺/环氧树脂固化体系较聚酰胺650/环氧树脂固化体系的固化活性大大提高,同时测定了该固化产物的热失重(TG)及玻璃化温度(Tg),对该固化物的热稳定性进行了评价,还测定了不同固化时间的剪切强度以研究其动态力学性能,从浇铸体的冲击强度方面比较其韧性。综合比较分析了聚酰胺固化剂与环氧树脂固化体系的力学性能、耐热性、电绝缘性等。结果表明:桐马聚酰胺Ⅲ型固化剂具有黏度低、粘接强度大、耐热性好、力学性能优等优点。     

Preparation and characterization study on maleic acid cross-linked poly(vinyl alcohol)/chitin/nanocellulose composites

In the quest on improving composite formulations for environmental sustainability, maleic acid (MA) cross-linked poly(vinyl alcohol) (PVA)-α-chitin composites reinforced by oil palm empty fruit bunch fibers (OPEFB)-derived nanocellulose crystals (NCC) had been successfully prepared. Based on the Fourier transform infrared (FTIR) spectroscopic analysis, it was proven that molecular interactions of the cross-linker to the polymeric networks was through conjugated ester linkage. Differential scanning calorimetry (DSC) showed that the influence of MA was minimal toward crystallization in the PVA/chitin/NCC composite. Maximum tensile strength, elongation at break and Young's modulus of the respective PVA/chitin/NCC composites were achieved at different content of MA, dependent on the PVA/chitin mass ratio. Among all compositions, a maximum Young's modulus was achieved at 30 wt% MA loading in PVA/chitin-30/NCC, amounting to 2,413.81 ± 167.36 MPa. Moreover, the mechanical properties and selected physicochemical properties (swelling, gel content, and contact angle) of the PVA/chitin/NCC composites could be tailored by varying the chitin content (10–30 wt%) and MA content (10–50 wt% based on total mass of composite). In brief, this chemically cross-linked PVA-based biocomposites formulated with sustainable resources exhibited tunable physicochemical and mechanical properties.