POLYMER ENGINEERING AND SCIENCE
·
2018
·Vol. 59
·期 4
·724-729
·
IF 1.551
Xiaoxia Jian,Yufang Song,Weiliang Zhou,Leqin Xiao
The correlation of diisocyanate structure with hydrogen bonding and microphase separation and further their influence on mechanical property was investigated in high soft segment (about 90 wt%) energetic poly(bis-azidomethyl oxetane/tetrahydrofuran) polyurethane binder. The hydrogen bonding analysis from Fourier transform infrared spectroscopy demonstrated that the limited intersegmental hydrogen bonding can occur in the hard domain, and small-angle X-ray scattering results also showed that the absence of high-order peaks in synthesized high soft segment polyurethanes. However, coplanar and symmetric diisocyanate and its inner benzene ring are favorable to ordered arrangement of hard segment, and further mircophase seperation enhance the tensile strength. POLYM. ENG. SCI., 59:724–729, 2019. © 2018 Society of Plastics Engineers
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
ADVANCED MATERIALS
·
2023
·
IF 29.4
Haiming Chen,Zaizheng Sun,Kai Lu,Jinming Liu,Chaobin He,Dongsheng Mao
The mechanism behind the resilience of polymeric materials, typically attributed to the well-established entropy elasticity, often ignores the contribution of enthalpy variation (Δ H ), because it is based on the assumption of an ideal chain. However, this model does not fully account for the reduced resilience of thermoplastic polyurethane (TPU) during long-range deformation, which is mainly caused by the dynamics of physical crosslink networks. Such reduction is undesirable for long-range stretchable TPU considering its wide application range. Therefore, a negative Δ H effect is established in this work to facilitate instant recovery in long-range stretchable TPU, achieved by constructing a reversible interim interface via strain-induced phase separation. Consequently, the newly constructed dual soft segmental TPU shows resilience efficiency exceeding 95%, surpassing many synthetic high-performance TPUs with typical efficiencies below 80%, and comparable to biomaterials. Moreover, a remarkable hysteresis loop with a ratio exceeding 50%, makes it a viable candidate for applications such as artificial ligaments or buffer belts. The research also clarifies structural factors influencing resilience, including the symmetry of the dual soft segments and the content of hard segments, offering valuable insights for the design of highly resilient long-range stretchable elastomers.
研究领域:
材料科学
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高分子化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2020
·
IF 3.573
Hangtian Zhang,Fang Zhang,Yixian Wu
Thermoplastic polyurethane (TPU) elastomers based on polyoxytetramethylene glycol (PTMG) with 2000 g·mol–1 as soft segments (SSs) and isocyanates as well as their reaction with butanediol as hard segments (HSs) were synthesized. The three-dimensional supramolecular networks were constructed in TPU by the formation of physical HSs-rich domains via microphase separation, hydrogen bonding, and microcrystallization, which are dominated by the chemical structure of HSs. The robust stretchable TPU with an excellent tensile strength of 32 MPa and elongation of 1378% at break could be successfully prepared, and no crystallization happened to keep the elasticity even at a low temperature (−90 °C) when the steric semisymmetric bis(4-isocyanatocyclohexyl)methane (HMDI) was introduced into HSs-rich domains. The crystallinity and ordered hydrogen bonding content decreased in HSs-rich domains with increases in steric hindrance and asymmetry of diisocyanates. A new approach was developed to construct the high-performance TPUs by introducing long PTMG SSs for the flexibility and elasticity and steric semisymmetric HMDI hard segments.
研究领域:
材料科学
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高分子化学
✓ 已验证
DOI
高影响因子
JOURNAL OF POLYMER SCIENCE
·
2024
·
IF 3.9
Hairui Wang,Yongxu Li,Hongyu Zhang,Xiurui Lang,Xiaolei Wang,Lan Cao,Chengzhong Zong
Thermoplastic polyurethane (TPU) with shape memory characteristics exhibits excellent comprehensive performance and structural design flexibility, wherein the composition and structure of the soft segment play a crucial role. We synthesized four linear-structured polyurethanes (PUs) using 4,4′-methylene diphenyl diisocyanate (MDI), polytetramethylene ether glycol (PTMG), and 1,4-butanediol (BDO) in identical molar ratios and systematically investigated the impact of soft segment molecular weight on hydrogen bonding, thermal properties, microphase separation, and mechanical performance of TPU. The results show that an increase in soft segment molecular weight leads to a reduction in hydrogen bonding, microphase separation, and modulus, while the tensile strength initially increases and then decreases. PU650 exhibits the highest hydrogen bonding index of 5.17 and the maximum microphase separation. Additionally, all TPU materials exhibit low-temperature multiple shape memory behavior and excellent recyclability. This work provides valuable insights into the structural design and performance optimization of recyclable PU materials. Graphical
研究领域:
材料科学
·
高分子化学
✓ 已验证
产品关联
DOI
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2024
·
IF 3.8
Liqian Zhu,Liang Zhu,Jijiang Hu,Zhen Yao,Zhiyang Bu,Suyun Jie,Bo-Geng Li
Polyurea elastomers with excellent mechanical properties are widely used in a variety of applications due to the unique microphase separation structure and high flexibility in formulations. A key point in the development of polyurea elastomers is to explore the structure–property relationship. However, few studies have focused on the effect of soft segment structures because of the limitation that the flexible soft segments are usually commercialized amine-terminated polyether. Herein, a series of polybutadiene-based polyurea elastomers were prepared to systematically investigate the influence of the network structures on the ultimate properties of the polyurea materials. In particular, the amine-terminated liquid polybutadiene rubber with tunable molecular weights and liquid polystyrene–butadiene rubber were synthesized via the degradation method for flexible regulation of the soft segment structure. The results demonstrated that performance optimization could be achieved by manipulating the degree of hydrogen bonding, which was controlled by the network structure. Besides, the polybutadiene-based polyurea elastomers exhibited excellent low-temperature properties, owing to the high cis-1,4 content.
研究领域:
材料科学
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高分子化学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF MATERIALS SCIENCE
·
2021
·Vol. 56
·期 20
·12018-12029
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IF 4.22
Chen Juan,Gong Caihong,Yang Ce,Yi Chunwang
The harsh synthesis conditions and lack of hard segments have long presented difficulties in the preparation of polyamide-based thermoplastic elastomers (TPAEs). In this work, a facile synthesis of TPAEs was developed using amide exchange. First, itaconic acid-polyoxypropylene diamine copolymer (IA-PPA) was synthesized by copolymerizing bio-based polyoxypropylene diamine (PPA D400) and itaconic acid (IA). The P2000 (IA-PPA with Mn ~ 2000) was then used as the soft segment of polyamide-6 based thermoplastic elastomers (PA6- b -P2000). Experimental results indicate that P2000 could directly initiate the ring-opening polymerization of caprolactam to form a prepolymer containing PA6 segments. PA6- b -P2000 thermoplastic elastomers were then obtained by the amide exchange reaction of PA6 segments. The structure and properties of IA-PPA and PA6- b -P2000 were further characterized in detail. The results demonstrate that the elastomers have good thermal stability and superior elasticity, which are highly dependent on the crystallinity and phase separation structure of the polyamide elastomer. Using this flexible approach, multifunction TPAEs can be designed and commercialized in a short time.
研究领域:
材料科学
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高分子化学
✓ 已验证
DOI
高影响因子
Polymer Chemistry
·
2018
·Vol. 9
·期 7
·869-877
·
IF 4.927
Bo Pang,Jingzhe Zhang,Minglei Pang,Peijian Zhao,Zhen Yang,Shengyu Feng,Jie Zhang
A new synthesis strategy was presented to prepare a polyurea–polysiloxane–polyether copolymer (PUA). A new block soft segment (b-SS) was synthesised via an aza-Michael addition reaction of acryloxymethyl-terminated polydimethylsiloxane (AT-PDMS) and amine-terminated polyoxypropylene (PPO). The hard segment (HS) was formed from bis(4-isocyanato cyclohexyl)methane (HMDI) and a 2-methyl-1,5-diaminopentane chain extender. The copolymers are tough and easily processed thermoplastic elastomers. The properties and structures of the polyurea–polysiloxane–polyether copolymers were investigated by dynamic mechanic analysis (DMA), small angle X-ray scattering (SAXS), atomic force microscopy (AFM) and macroscopy mechanical testing. The DMA results of the polyurea–polysiloxane–polyether copolymers show that temperature insensitive rubbery plateaus exist between −50 °C and 80 °C, which are independent of the HS wt% and the molecular weight of PDMS. The viscoelastic behavior of the polyurea–polysiloxane–polyether copolymers was correlated with the molecular weight of PDMS used for the b-SS. The polyurea–polysiloxane–polyether copolymers display improved mechanical strength (16 MPa) compared with the published results of PDMS-based siloxane-urea segmented copolymers (11–13 MPa). The studies reveal that the mild microphase separation between the hard and soft segments leads to improved mechanical strength of the polyurea–polysiloxane–polyether copolymers. In addition, for these copolymers, the introduction of b-SS is effective in avoiding a sharp phase separation assuming that the molecular weight of PDMS in the b-SS is appropriate.
研究领域:
材料科学
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高分子化学
✓ 已验证
产品关联
DOI
高影响因子
EUROPEAN POLYMER JOURNAL
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2021
·
IF 4.598
Zhengkai Wei,Zhimeng Liu,Xiaowei Fu,Yuechuan Wang,Anqian Yuan,Jingxin Lei
A series of solvent-free waterborne polyurethanes (WPUs) with different soft segment structure were prepared by respectively using different number-average molecular weight ( M n ) of polytetramethylene glycol (PTMG, M n = 1000, 2000, 3000) and poly (1,4-butylene adipate) (PBA, M n = 1000, 2000 3000) as main diol in this paper. Effect of soft segment crystallization on water resistance of WPUs was discussed. The crystallization properties of WPU films were investigated by differential scanning calorimetry (DSC) and X-ray diffraction (XRD). The water resistance was determined by water absorption ratio. DSC and XRD results confirm that there are no crystalline structures in the WPU films which are synthesized with PTMG ( M n = 1000, 2000, 3000) and PBA ( M n = 1000), while the WPU films synthesized with PBA ( M n = 2000 and 3000) have obvious crystalline structures at room temperature. Meanwhile, the WPU films synthesized with PBA ( M n = 2000 and 3000) possess excellent water resistance because the existence of crystalline structure.
研究领域:
材料科学
·
高分子化学
✓ 已验证
DOI
高影响因子
Applied Materials Today
·
2021
·
IF 10.041
Juan Liu,Zhigang Chen,Chengshen Hu,Wei Yang,Jinfeng Wang,Weilong Xu,Yuanliang Wang,Changshun Ruan,Yanfeng Luo
Shape memory polyurethanes (SMPUs) with excellent shape memory effects (SMEs) can be served as a kind of smart materials capable of responding to external stimuli. Microphase separation behavior between soft and hard segments of SMPUs is recognized as structural basis and an intrinsic factor for SMEs of SMPUs. Therefore, effective detection of microphase separation behavior is highly desired in order to clarify the mechanism of SMEs and further regulate the SMEs of SMPUs. Although great progresses have been made in detection of microphase separation behavior of SMPUs, non-destruction and real-time visualization for tracking the microphase separation behavior during the shape memory process of SMPUs remains a great challenge. Herein, a facile fluorescence visualization method is presented to directly, fast and nondestructively monitor the microphase separation behavior of SMPUs. Specifically, a series of novel inherent fluorescent SMPUs (IFPUs) with different hard segment contents (10%, 15% and 20%) were first prepared by using a fluorescent small molecule as part of their hard segments. It was found that this fluorescent molecule could visualize the aggregation of hard segments and the corresponding microphase separation behavior in a real-time manner. Moreover, by conducting a semi-quantitative calculation of the collected fluorescent images, the size, aspect ratio and orientation of the hard segment domains could be obtained. The results indicated that increasing the contents of hard segments could enhance the microphase separation and both stretching (50%, 100% and 200%) and subsequent recovering processes could promote the formation of larger and longer hard segment domains tending to take a perpendicular orientation to stretching.
研究领域:
材料科学
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高分子化学
✓ 已验证
产品关联
DOI
高影响因子
Materials
·
2020
·Vol. 13
·期 21
·4991
·
IF 3.057
Xin Jin,Naisheng Guo,Zhanping You,Yiqiu Tan
Thermoplastic polyurethane elastomers (TPUs) are widely used in a variety of applications as a result of flexible and superior performance. However, few scholars pay close attention on the design and synthesis of TPUs through the self-determined laboratory process, especially on definite of chemical structures and upon the influence on properties. To investigate the properties of synthesized modifier based on chemical structure, firstly each kind of unknown structure and composition ratio of TPUs was determined by using a new method. Furthermore, the thermal characteristics and mechanical properties of modifiers were exposed by thermal characteristics and mechanics performance tests. The experimental results indicate that TPUs for use as an asphalt modifier can successfully be synthesized with the aid of semi-prepolymer method. The linear backbone structure of TPUs with different hard segment contents were determined by micro test methods. The polyester-based TPUs had thermal behavior better than the polyether-based TPUs; conversely, the low temperature performance of polyether-based TPUs was superior. Most importantly, it was found that the relative molecular mass of TPUs exhibited a weak effect on the mechanical properties, whereas the crystallinity of hard segment showed a significant influence on the properties of TPUs.
研究领域:
材料科学
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化学工程
✓ 已验证
DOI
高影响因子
EUROPEAN POLYMER JOURNAL
·
2022
·
IF 5.546
Jinbao Xu,Wenhao Xiao,Siheng Zhang,Zhixian Dong,Caihong Lei
Development of controllable, versatile and robust degradable polyurethane (PU) is of continued attraction regarding its wide application in the field of biology and medicine. Herein, new degradable poly(ether-ester-urethane) (PEEU) with amorphous and hydrophilic poly(1,5-dioxepan-2-one) (PDXO) diols as the soft segments and 4,4-diphenylmethane diisocyanate (MDI) and butane-1,4-diols (BDO) as the hard segments was synthesized by the one-shot two -step method in a controllable manner. The degradation behavior of PEEU with various compositions in vitro was investigated by observing the changes of weight loss, molecular weight and surface morphology during the 140 days of degradation. The weight loss and degradation rate of PEEU were faster than that of PU with semi-crystallized poly( ε -caprolactone) diols as soft segments and a surface to bulk degradation process was observed by scanning electron microscopy (SEM). In addition, the weight loss decreased by increasing the hard segments composition and the weight loss was mainly from the hydrolysis of ester linkages.
研究领域:
生物材料学
·
医学材料
✓ 已验证
DOI
高影响因子
GREEN CHEMISTRY
·
2016
·Vol. 18
·期 12
·3614-3619
·
IF 8.506
Zhong Ying,Chaoyong Wu,Shan Jiang,Ruhui Shi,Bin Zhang,Chao Zhang,Fengyu Zhao
A series of thermoplastic polyurethane-ureas were synthesized from a soft segment of a polycarbonate diol and a hard segment of an oligourea, and both the segments were derived from the CO2-route. The chemical structure of the synthesized segments and final polyurethane-ureas were identified by FT-IR and 13C-NMR. The average molecular weight of the oligourea was detected by potentiometric titration, MALDI-TOF and GPC. The Mn and Mw of the final polyurethane-ureas were nearly 0.7 × 104 Da and 1.0 × 104 Da, respectively, within a polydispersity index (PDI) of 1.27–1.44. Moreover, the X-ray diffraction (XRD) results showed that the as-synthesized polyurethane-ureas were amorphous and presented moderate thermo-stable properties with an initial decomposition temperature higher than 170 °C and a maximum decomposition temperature around 250 °C as examined by TGA. Furthermore, the amorphous polyurethane-ureas have a good solubility in some traditional organic solvents because the siloxane and carbonate groups were introduced into the main chain. The present novel polyurethane-urea, which possesses a high flexibility and fine compatibility with other polymeric materials, will have a wide application as a macromolecular plasticizer in plastic materials.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）