2012届硕士毕业生
发布人： 发布时间: 2014-02-27 作者: admin 访问次数: 116

 

论文题目：聚酰胺酸改性环氧树脂及其碳纤维增强复合材料的制备
毕业学生：刘勇
指导老师：吴唯教授
中文摘要：
       本课题以环氧树脂E-51和环氧树脂CYD-011以1:1的配比混合液作为基体，以聚酰亚胺的前聚体聚酰胺酸为改性剂，预先对环氧树脂浇铸体进行改性，随后将改性后的树脂作为树脂基体用于制备碳纤维增强环氧树脂复合材料板材。本实验通过傅利叶红外光谱（FTIR）研究了聚酰胺酸与环氧树脂之间的预反应，通过差示扫描量热法（DSC）聚酰胺酸的加入对环氧树脂/DDS固化体系的固化温度、固化速率及固化反应活化能的影响，通过热失重分析（TGA）考察了聚酰胺酸的加入对环氧树脂热稳定性的影响。此外，作为本实验的主要目标之一，考察了聚酰胺酸改性后的环氧树脂体系的力学性能尤其是冲击韧性和平面断裂韧性的变化，并对聚酰胺酸对环氧树脂的改性机理做了一定的分析。结果表明，聚酰胺酸的加入，使环氧树脂的固化起始温度下降了55.7℃，由高温固化转变为近中温固化；固化凝胶时间缩短了72%，固化反应活化能降低了15.6KJ/mol，耐热温度也有所提高；在力学性能方面，聚酰胺酸的加入使得冲击强度提高了近190%， 平面断裂韧性提高了56%，弯曲强度提高了15%。将改性后的环氧树脂体系采用溶液法与碳纤维预浸，通过溶液法制备预浸料，达到预浸料制备的标准。随后采用制备的预浸料制备出碳纤维增强复合材料，并对复合材料板材的力学性能进行表征。结果表明，聚酰胺酸的加入使得复合材料的弯曲强度提高了47.5%，层间剪切性能提高了33.5%，初始层间剥离韧性提高了近250%，平均剥离韧性提高了19.7%。此外，对聚酰胺酸改性环氧树脂及其碳纤维增强复合材料的机理也作了一定的分析。
       本课题综合考察了聚酰胺酸对环氧树脂固化行为、耐热性能和力学性能的影响，并探索性使用聚酰胺酸改性后的环氧树脂制备碳纤维增强复合材料，对拓宽环氧树脂的应用及高性能复合材料的制备有一定的实际意义。 
Abstract：
In this paper, the epoxy E-51 and CYD-011 were blended as the matrix resin with the ratio of 1:1, and the polyamic acid which is the processor of polyimide was used as the modifier. The epoxy resin was modified by polyamic acid followed by the preparation of carbon fiber reinforced epoxy composites at the first time. The pre-reaction of the epoxy and polyamic acid was study by Fourier Transform Infrared Spectroscopy (FTIR), the curing behaviors including the curing temperature, curing rate and curing activation energy of epoxy resin systems were studied by Differential Scanning Caborimetry (DSC), the effects of polyamic acid on the mechanical properties including the impact strength, the tensile strength and modulus, the flexural strength and modulus were studied at the same time. The results show that, by adding polyamic acid into the epoxy and after the pre-reaction, the initial curing temperature of the epoxy/DDS systems was decreased about 55.7℃, the gel-time of the resin system shorten about 72% when compare with the resin without modifying, the activation energy of the resin was lowered about 15.6KJ/mol, and the ability of thermal resistance for the resin was increased to some extent. As for the mechanical properties for the modified resin system, the impact strength of the resin with 2wt% polyamic acid was increased about 190%, the plain strain fracture toughness was increased 56% and the flexural strength was increased about 15% comparing with the resin without polyamic acid. Then the modified resin was used to prepare the carbon fiber reinforced epoxy composite through the solution method. The mechanical properties of composite laminates were conducted by tensile test machine. The test results show that the flexural strength of the composites laminates made by the modified resin matrix was increased 47.5%, the inter-laminar shear strength was increased about 33.5%, and the initial inter-laminar delamination strength was increased about 250%. The mechanism of the modification of polyamic acid to epoxy resin matrix and composite were also analyzed and the formation of semi-IPN structure was proposed to be the main reason for the improvement.

 

 

论文题目：碳纤维增强环氧树脂预浸料及其复合材料的制备与性能研究
毕业学生：刘明昌
指导老师：吴唯教授
中文摘要：
       本文以固、液环氧树脂的复配体系为树脂基体，选择了液体环氧树脂E-51、固体环氧树脂CYD-011和固化剂4,4’-二氨基二苯基砜（DDS，[(NH2)]C6H4]2SO2）作为树脂基体组分，研究了碳纤维增强环氧树脂预浸料的制备及其复合材料的性能。根据热熔膜法制备预浸料的要求，通过对树脂基体配方研究得知，当E-51环氧树脂:CYD-011环氧树脂:DDS=50:50:22.58时能得到具有一定强度和韧性，可弯曲而不断裂的树脂胶膜。并经过对碳纤维增强环氧树脂复合材料的制备工艺研究，含胶量为40%较为合适，固化制度为140℃/2h+160℃/2h+180℃/2h、压力为0.4~0.6MPa、加压点为140℃/1h时复合材料力学性能为最优，复合材料的0°弯曲强度为1478MPa，层间剪切强度为82MPa。在文中，还采用等温DSC法研究了环氧树脂与4,4’-二氨基二苯基砜(DDS)体系的固化反应过程，研究发现固化反应中出现“转折点”，当固化度小于50%时属于Kamal自催化模型；当固化度大于50%时属于n级固化模型，即固化反应由Kamal自催化反应向n级反应转变。转变后，反应活化能有所下降。
Abstract：

Based on solid and liquid epoxy resin system for resin matrix composite, liquid epoxy resin E-51, solid epoxy resin CYD-011 and curing agent 4, 4’-Diaminodiphenylsulfone (DDS) were chosen as the matrix resin component, and the carbon fiber reinforced epoxy resin pre prepreg preparation and properties of its composite were researched. According to the hot melt film preparing prepreg’s requirements, when each component mass ratio was: epoxy resin E-51: epoxy resin CYD-011: DDS = 50:50: 22.58 and could be obtained the resin film with certain strength and toughness, and could be bent without breaking. The results showed that resin quality content of prepreg being 40% was preferred, and when curing process was: curing temperature-time being 140℃/2h+160℃/2h+180℃/2h, pressure being 0.4~0.6MPa, pressure point being 140℃/1h, carbon fiber reinforced epoxy resin composite mechanical properties were optimal, and flexural strength was 1478Mpa and interlaminar shear strength was 82MPa. In this paper, the experimental data for characterizing and the curing kinetics for E-51/CYD-011 epoxy resins were determined using a DSC isothermal scan method and isothermal curing kinetics parameters were obtained through fitting between the experimental data and the curing models. The reaction process shows to be dominated by a different mechanism at different stages of the E-51/CYD-011 system curing process: when the cure degree was less than 0.5, the curing system was an autocatalytic reaction model; when the cure degree was more than 0.5, the curing system was an nth order reaction model, with an initial autocatalytic reaction shifting into an nth order reaction as the reaction proceeding. After the change, the reaction activation energy decreased.

 

 
论文题目：碳纤维增强聚对苯二甲酸乙二醇酯复合材料的制备和性能研究
毕业学生：石品品
指导老师：吴唯教授
中文摘要：
       本课题以聚对苯二甲酸乙二醇酯（PET）为基体，2mm的短切碳纤维（SCF）为增强材料，采用双螺杆挤出机通过熔融共混法制备了PET/SCF复合材料。对工艺条件进行了探索，研究了碳纤维含量及碳纤维表面处理对PET/SCF复合材料性能的影响及其机理。结果表明，当添加未经表面处理的碳纤维时，随着碳纤维含量的增加，复合材料的拉伸强度，弯曲强度，弯曲模量这些力学性能均增加，冲击强度先增加后减小，热稳定升高，熔融流动性先升高后降低，结晶性能变好。通过对浓硝酸，钛酸酯偶联剂，硅烷偶联剂对碳纤维表面改性效果的对比，选用了浓硝酸加硅烷偶联剂复合处理的方法对碳纤维表面改性。与未经表面处理的碳纤维增强复合材料相比，经表面处理过的碳纤维复合材料的拉伸强度整体平均提高了15%左右，弯曲强度提高了22%左右，弯曲模量提高了15%左右，冲击强度提高了13%左右，硬度提高了10%左右。碳纤维经表面处理后对复合材料的热稳定性影响不大。结晶温度和熔融温度有所提高，结晶速度增加，结晶度降低。流动性能也得到改善，复合材料的损耗因子降低，材料的耐使用性也得到了改善。
Abstract：
In this paper, PET and SCF with 2mm length were chosen to prepare for PET/SCF composites by melt extrusion processing. The optimum process conditions were obtained through experiments, and we studied SCF content and the surface treatment influence on the properties of composites. Research showed that tensile strength, flexural strength, flexural modulus was increased with increased SCF content expect impact strength and meltfludity which increased first and then decreased. Addition of SCF brought faster crystallization and better thermostability. Concentrated nitric acid, silane coupling agent, titanate coupling agent were used to treat carbon fiber surface. When carbon fiber was treated with concentrated nitric acid and silane coupling agent, the composite has the best mechanical properties. Results showed that when carbon fiber surface was treated, the tensile strength of the composite increased 15%, while the flexural strength increased 22%, the flexural modulus increased 15%, the impact strength increased 13%, and the hardness increased 10%. Carbon fiber surface treatment had no influence on the thermostability of the composite and brought faster crystallization. The meltfludity and the usability of the composite also improved after carbon fiber surface treatment.  

 

 

论文题目：热熔膜法长效低温碳纤维/环氧树脂预浸料的制备及性能研究
毕业学生：吴祥
指导老师：吴唯教授
中文摘要：
       本研究以固态、液态双酚A环氧树脂的复配体系为树脂基体、甲基纳迪克酸酐（MNA）为固化剂，将通常用作阳离子型表面活性剂和相转移催化剂的苄基三乙基氯化铵（BTEAC）作为促进剂，碳纤维作为增强材料，采用热熔膜法制备长效低温固化碳纤维增强环氧树脂预浸料。 通过差示扫描量热仪、旋转流变仪等手段重点研究了固化剂和促进剂的用量对环氧树脂胶膜的成膜性、成膜工艺、固化温度和室温贮存期的影响。研究结果表明，当环氧树脂/固化剂/促进剂的质量比为100/48～51/1.5～2时，制备的环氧树脂胶膜室温下韧性良好、不黏手不黏纸，能在85℃下完成初步固化，同时在室温下的粘性贮存期为8天。
       用上述优化的配方制得的环氧树脂胶膜与碳纤维复合，制备碳纤维/环氧树脂预浸料。通过研究热辊温度、热压次数及热辊转速对预浸料浸渍性的影响，确定了预浸料的最佳成型工艺。研究结果表明，当热辊温度为65℃～70℃，热辊转速为3m/min～4m/min，热压次数为13次～17次时，环氧树脂对碳纤维的浸润效果最好，且预浸料的各项物理性能均匀稳定。采用模压成型法将上述预浸料制备成单向复合材料层压板，测定了复合材料的力学性能、吸水性能和耐湿热性能，并通过扫描电子显微镜研究了复合材料的断面形貌。研究结果表明，复合材料具有良好的力学性能，其弯曲强度为1025MPa，层间剪切强度为70MPa，且该复合材料具有良好的界面粘结性，吸水率较少、耐湿热性优良。
Abstract：
In this paper, with the combination system of the solid and liquid bisphenol A epoxy reisn for resin matrix, MNA as curing agent, BTEAC commonly used for phase transfer catalyst and cationic surfactants as accelerator, carbon fiber as strength material, the long shelf life and low temperature prepreg was prepared by the hol-melt route. The effect of the content of curing agent and accelerator on the film property, the viscosity-temperature characteristics, curing temperature and shelf life at RT was investigated by the DSC and rotational rheometer.The results show that the formula involves epoxy resin/curing agent/accelerator with mass proportion of 100/48～51/1.5～2.The epoxy resin film prepared by this system can be cured at 85℃, have excellent film forming properties and shelf life at RT for 8days.
The carbon fiber/epoxy resin prepreg was prepared by the carbon fiber and epoxy resin film obtained by optimized epoxy resin formula.The effect of hot roller temperature, pressing times and line speed on the prepreg impregnation were investigated. The results show that the impregnation effect was the best , and the physical properties of prepreg is uniform and stable when the hot roller temperature was 65℃～70℃, line speed was 3m/min～4m/min, pressing times was 13times～17times. The unidirectional composites laminates were prepared by the moulding process.The mechanical properties, water absorption, hygroscopicity and fracture morphology were studied.The results show that the composites had excellent mechanical performance, such as flexural strength was 1025MPa, interlaminar shear strength was 70MPa. The composites had good interface bonding performance, low water absorption and low hygroscopicity.

 

  

论文题目：环保阻燃ABS树脂开发及工业化研究
毕业学生：张秀玲
指导老师：吴唯教授
中文摘要：
       文叙述环保阻燃ABS树脂开发及工业化研究，解决ABS阻燃改性以及改性后的ABS工业化生产的技术问题。包括ABS生产工艺原理、阻燃原理的研究；通用ABS 0215A的阻燃改性技术研究；改性后产品生产工艺研究；工业化生产等方面。
       以吉林石化ABS装置为基础，调整ABS粉料及SAN比例，以符合ROHS法令的溴系阻燃剂复配三氧化锑为阻燃体系，利用中试双螺杆挤出机研究开发阻燃ABS。研究结果表明，Br含量大于8%以后才能满足UL-94的V-0级要求；Sb2O3 含量增加对阻燃有利，但冲击强度下降，通过试验选用Sb2O3/Br的比为1∶2；在ABS加工成型的温度条件下,TBBPA流动性极佳，在ABS分子间充当了内润滑剂，选用四溴双酚A阻燃体系开发系列阻燃ABS产品，在降低能耗同时提高生产效率；高胶粉料的增韧效果最好，为阻燃ABS首选增韧剂；通过试验阻燃ABS有着较宽的加工范围，拉伸强度、弯曲强度基本不随加工条件改变，一定的加料量条件下适当的螺杆转速会提高阻燃ABS冲击强度。
通过稳定性试验表明，中试生产工艺条件为：挤出温度：180℃；螺杆转速：220-240rpm；加料量为：90Kg/hr(注：为避免物料在加料口熔化堵塞，挤出机加料口温度设为170℃)，生产工艺参数稳定，易于控制，产品质量稳定性好，冲击强度、热变形温度等指标明显高出预期指标，具备了工业化的条件。
Abstract：
The research on the development and industrialization of environmentally friendly flame retardant ABS resin is described in this thesis which gives solutions to the technical issues of the ABS flame retarding modification and the industrialized production of the modified ABS resin. This thesis mainly focuses on the following aspects: The process principle and flame retarding principle of the ABS production; the flame retarding modification technique of general ABS 0215A; the production technology and the industrialization of the modified product. 
Based on the ABS plant of Jilin Petrochemical Company, using pilot scale twin-screw extruder research and develop the flame retardant ABS by adjusting the ratio of ABS and SAN powder and adopting the bromide flame retardant complies with ROSH legislation formulated by antimony trioxide as flame retarding system. The result proves that the UL-94 can achieve V-0 class when Br content is higher than 8%; the increase of Sb2O3 content can enhance the flame retarding effect but drop the impact strength and by experiment the ratio between Sb2O3 and Br is set at 1:2; TBBPA flame retardant has excellent flow ability at ABS molding temperature and becomes lubricant between ABS molecules and by adopting it in the development of flame retardant ABS can not only reduce energy consumption but also improve production efficiency; High emulsion power is the preferred toughening agent of flame retardant ABS due to its excellent toughening property; It is proved by experiment that the flame retardant ABS has features of wide-range process capability, stable tensile and flexible strength under different processing conditions and the impact strength can be enhanced by adjusting the screw rotation speed to an appropriate value with the same feeding rate.
The stability test result indicates that the process requirement for pilot scale production is as following: extruding temperature: 180℃；Screw rotation rate: 220-240rpm; Feeding rate: 90Kg/hr (Note: To avoid the melting product blocking the feed inlet, the extruder feed inlet temperature should be set at 170 ℃). The production process parameters are stable and ease to control, product owns high standard of quality and stability whose impact strength and distortion temperature etc. are markedly higher than the expected parameters. The industrialized production can be implemented.

 

 

论文题目：多元氢键自组装热回复性超分子聚合物的合成与研究
毕业学生：陈玉洁
指导老师：吴唯教授

中文摘要：

       本论文以氢键联接小分子或低聚物自组装形成物理网状结构超分子弹性体聚合物概念为基础，设计与合成了新型热回复性多元氢键超分子聚合物。采用简便的一锅法反应成功制备了一系列由酰胺低聚物及其封端产物分子链间通过多元氢键联接自组装形成的氢键超分子聚合物，对其分子结构、分子量及其分布、机械性能、结晶与熔融、热稳定性、热回复与加工性能、类橡胶弹性、动态流变性能等进行了详细表征。本论文提出了多元氢键超分子聚合物的相转变模型，并对其分子链动力学、氢键热动力学和自组装机理进行了深入探讨。

       分别通过二聚脂肪酸（DFA）和乙二胺（EAH）的酰胺缩聚反应和对甲苯磺酰异氰酸酯（PTSI）的封端反应，并改变二聚脂肪酸种类（BX-1和BX-4）和异氰酸酯含量，成功制备了一系列不同配方的酰胺低聚物BX-1-EAH和PTSI封端的酰胺低聚物BX-1-EAH-PTSI和BX-4-EAH-PTSI，产物在冷却过程中，低聚物分子链之间通过多元氢键联接自组装形成物理网状结构的氢键超分子聚合物。由1H-NMR和FT-IR分析证实，在氢键超分子聚合物的制备中成功发生了酰胺化反应和异氰酸酯的封端反应，且最终形成的氢键超分子聚集体中存在大量分子链上酰胺基团、磺酰脲基团间形成的C=O······NH、S=O······NH多元氢键，表明超分子聚合物具备氢键物理网状结构。GPC和ESI-TOF-MS测试表明，酰胺低聚物的分子量较低，且具有较宽的分子量分布，推断三种低聚物的聚合度低于10。
        氢键超分子聚合物具有优良的机械性能，拉伸强度最高达13.2MPa，球压痕硬度最高为20.3N/mm2。当乙二胺与二聚酸的摩尔比为1.2:1时，氢键超分子聚合物得到最高的拉伸强度和断裂伸长率。以BX-4为原料的氢键超分子聚合物不溶凝胶含量为3.2%，产生更多的支化交联微区，拥有更高的拉伸强度、模量和硬度。氢键超分子聚合物具有氢键物理交联网络与化学交联微区并存的结构形式，DMA结果表明氢键超分子聚合物在低温下（< -30°C）处于玻璃态，呈现出硬塑料的性质；在10°C左右发生了玻璃化转变过程，产物在Tg和室温之间呈现出高弹态，在室温时体现为橡胶弹性性质。  
氢键超分子聚合物熔点低，样品熔点范围在88-100°C；结晶度小，熔融焓（ΔHm）值范围在8.5-12.5J/g；热稳定性好，热失重10%的分解温度（Td10）均在340°C以上。产物具有良好的热回复性，可采用通用熔融成型加工设备对材料进行成型加工。氢键超分子聚合物具有延迟回复性能的软橡胶性质，在玻璃化温度（Tg）和熔融温度（Tm）之间表现为类橡胶弹性。氢键超分子聚合物熔体为具有很高屈服应力值的非线性Bingham流体。氢键超分子聚集体具有动态层状有序结构相和化学交联微区不均匀分布在三维网状结构无序相中的多相结构，在Tc1≈ 90°C下发生类弹性固-液相变，在Tc2处发生液-液转变的微相分离。氢键超分子聚合物的松弛过程是物理作用的缔合-解缔合机理和蠕动机理共同影响的结果。平均松弛时间均随着温度的升高而不断缩短，零剪切粘度也随着温度的升高而不断降低。
高温下酰胺低聚物分子链之间的氢键密度很低，体系表现为低粘度液体；降温过程中，氢键密度增加，分子链之间通过多元氢键作用自组装，分子链有序性增加；在90°C左右，体系粘度、储存模量突然增加，氢键超分子聚合物发生液-固转变；由90°C继续冷却，三维氢键网络中形成少量层状动态有序结构，室温时氢键超分子聚合物体现为粘弹性固体，具有一定结晶性和良好的机械性能。在升温、降温的过程中，物理交联网状结构破坏与重组，氢键自组装过程具有可逆性。
Abstract：
In this thesis, new thermorebersible multiple hydrogen-bonding supramolecualr polymers are designed and synthesized from the concept that multiple hydrogen- bonding supramolecular elastomers with physical network structure are assembled from small molecules or oligomers associated by hydrogen bonds. Hydrogen-bonding supramolecular polymers are successfully prepared by one-pot synthesis from a series of amide and end-capped amide oligomer assembled by multiple hydrogen bonds between chains. Molecular structure, molecular weight and distribution, as well as mechanical, crystallization and melting, thermal decomposition, thermoreversible and processing, rubber-like, dynamical rheological properties are well characterized. The mode for phase transition, chain dynamics, hydrogen-bonding thermodynamics and assembling mechanism of multiple hydrogen-bonding supramolecular polymers are proposed and discussed in this thesis.
Amide oligomer BX-1-EAH and end-capped amide oligomers BX-1-EAH-PTSI and BX-4-EAH-PTSI are synthesized from the condensation polymerization of dimer fatty acid (DFA) and anhydrous ethylene diamine (EAH) and then end-capped reaction by adding to p-toluenesulfonyl isocyanate (PTSI) with variable kinds of dimer fatty acid (BX-1 and BX-4) and contents of isocyanate. At cooling of products, oligomer chains assemble to physical network hydrogen-bonding supramolecular polymer by multiple hydrogen-bonding connections between chains. 1H-NMR and FT-IR analyses conform that amidation reaction and isocyanate end-capped reaction are successful and multiple hydrogen bonds of CO······NH, S=O······NH between amide and sulfonyl urea groups exist in the hydrogen-bonding supramolecular assembly which indicates the hydrogen-bonding physical network structure of supramolecular polymer. GPC and ESI-TOF-MS characterization show that amide oligomers have low molecular weight and wide molecular weight distribution and polymerization degree of the three oligomers is below 10.
Highest ensile strength 13.2 MPa and ball indentation hardness 20.3 N/mm2 indicate that hydrogen-bonding supramolecular polymers have excellent mechanical properties. When molar ratio of EAH and DFA is 1.2: 1, tensile strength and elongation reach the highest value. Hydrogen-bonding supramolecular polymer with BX-4 as starting materials has 3.2% indissoluble gel and more chemical crosslinking micro-region from branching, and has higher tensile strength modulus and hardness. Physical network and chemical crosslinking micro-region coexist in hydrogen- bonding supramolecular polymers. DMA results indicate that at low temperature (< -30°C) hydrogen-bonding supramolecular polymers behave like hard plastic at glass state and the glass transition is at around 10 °C. Products show high-elastic properties between Tg and room temperature and rubber-like behavior at room temperature.
DSC and WXRD results indicate the low melt temperature (88-100°C) and degree of crystalline (ΔHm = 8.5-12.5J/g); TGA show the excellent thermal stability of supramolecular polymer and the 10% decomposition temperature (Td10) is > 340 °C. The materials have good thermoreversible behavior, hence the moulding process can be operated on general melting mouldling processing equipments. Force-free tensile test indicates that the hydrogen-bonding supramolecular polymers behave like soft rubber with delayed recovery and show rubber-like elasticity between Tg and Tm.
Rotational rheological characterization indicates that the melt of hydrogen- bonding supramolecuar polymer behaves like non-linear Bingham flow with very high yield stress. Hydrogen-bonding supramolecular assembly has multi phases including dynamic lamellar ordered phase and 3D network disordered phase with heterogeneous chemical crosslinking micro-regions. Rubber-like solid-liquid transition is at Tc1≈ 90°C, and liquid-liquid transition of micro-phase separation is at Tc2. Associate-disassociate mechanism of physical interaction and reptation mechanism have cooperatively effect on the relaxation of hydrogen-bonding supramolecular polymer. The mean time of relaxation decreases and the zero shear viscosity with the increase of temperature.
At high temperature, the density of hydrogen bonds between oligomer chains is very low, and the system behaves like liquid with low viscosity; at cooling, the hydrogen-bonding density increases, molecular chains assemble by multiple hydrogen-bonding and the order degree of chains increases; viscosity and storage modulus of the system suddenly increases at around 90°C, and the supramolecular polymer has liquid-solid transition; below 90°C, a few dynamic ordered lamellar structures form in the 3D hydrogen-bonding networks, and until room temperature, hydrogen-bonding supramolecular polymer behaves like viscoelastic solid with low crystalline and good mechanical properties. At the heating and cooling cycles, physical cross-linking networks are destroyed and reformed, therefore, the assembling process from hydrogen-bonding is reversible.