Mechanical properties of thermoplastic polyurethanes containing aliphatic polycarbonate soft segments with different chemical structures

2002 ◽  
Vol 42 (6) ◽  
pp. 1333-1349 ◽  
Author(s):  
Hideho Tanaka ◽  
Masaru Kunimura
Keyword(s):  
Mechanical Properties ◽  
Thermoplastic Polyurethanes ◽  
Chemical Structures ◽  
Aliphatic Polycarbonate ◽  
Soft Segments

scholarly journals Studies on the Modification of Commercial Bisphenol-A-Based Epoxy Resin Using Different Multifunctional Epoxy Systems

2021 ◽  
Vol 2 (2) ◽  
pp. 419-430
Author(s):  
Ankur Bajpai ◽  
James R. Davidson ◽  
Colin Robert
Keyword(s):  
Mechanical Properties ◽  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Bisphenol A ◽  
Epoxy Resin ◽  
Tensile Fracture ◽  
Chemical Structures ◽  
Amino Phenol ◽  
Epoxy Systems

The tensile fracture mechanics and thermo-mechanical properties of mixtures composed of two kinds of epoxy resins of different chemical structures and functional groups were studied. The base resin was a bi-functional epoxy resin based on diglycidyl ether of bisphenol-A (DGEBA) and the other resins were (a) distilled triglycidylether of meta-amino phenol (b) 1, 6–naphthalene di epoxy and (c) fluorene di epoxy. This research shows that a small number of multifunctional epoxy systems, both di- and tri-functional, can significantly increase tensile strength (14%) over neat DGEBA while having no negative impact on other mechanical properties including glass transition temperature and elastic modulus. In fact, when compared to unmodified DGEBA, the tri-functional epoxy shows a slight increase (5%) in glass transition temperature at 10 wt.% concentration. The enhanced crosslinking of DGEBA (90 wt.%)/distilled triglycidylether of meta-amino phenol (10 wt.%) blends may be the possible reason for the improved glass transition. Finally, the influence of strain rate, temperature and moisture were investigated for both the neat DGEBA and the best performing modified system. The neat DGEBA was steadily outperformed by its modified counterpart in every condition.

scholarly journals Sulfonated Binaphthyl-Containing Poly(arylene ether ketone)s with Rigid Backbone and Excellent Film-Forming Capability for Proton Exchange Membranes

Polymers ◽  
2018 ◽  
Vol 10 (11) ◽  
pp. 1287 ◽  
Author(s):  
Wenmeng Zhang ◽  
Shaoyun Chen ◽  
Dongyang Chen ◽  
Zhuoliang Ye
Keyword(s):  
Mechanical Properties ◽  
Proton Conductivity ◽  
Proton Exchange Membrane ◽  
Proton Exchange ◽  
Thermal Stabilities ◽  
Chemical Structures ◽  
Arylene Ether ◽  
Film Forming ◽  
Ether Ketone ◽  
Microscopic Morphology

Sterically hindered (S)-1,1′-binaphthyl-2,2′-diol had been successfully copolymerized with 4,4′-sulfonyldiphenol and 4,4′-difluorobenzophenone to yield fibrous poly(arylene ether ketone)s (PAEKs) containing various amounts of binaphthyl unit, which was then selectively and efficiently sulfonated using ClSO3H to yield sulfonated poly(arylene ether ketone)s (SPAEKs) with ion exchange capacities (IECs) ranging from 1.40 to 1.89 mmol·g−1. The chemical structures of the polymers were confirmed by 2D 1H–1H COSY NMR and FT-IR. The thermal properties, water uptake, swelling ratio, proton conductivity, oxidative stability and mechanical properties of SPAEKs were investigated in detail. It was found that the conjugated but non-coplanar structure of binaphthyl unit endorsed excellent solubility and film-forming capability to SPAEKs. The SPAEK-50 with an IEC of 1.89 mmol·g−1 exhibited a proton conductivity of 102 mS·cm−1 at 30 °C, much higher than that of the state-of-the-art Nafion N212 membrane and those of many previously reported aromatic analogs, which may be attributed to the likely large intrinsic free volume of SPAEKs created by the highly twisted chain structures and the desirable microscopic morphology. Along with the remarkable water affinity, thermal stabilities and mechanical properties, the SPAEKs were demonstrated to be promising proton exchange membrane (PEM) candidates for potential membrane separations.

scholarly journals Structural and Viscoelastic Properties of Thermoplastic Polyurethanes Containing Mixed Soft Segments with Potential Application as Pressure Sensitive Adhesives

Polymers ◽  
2021 ◽  
Vol 13 (18) ◽  
pp. 3097
Author(s):  
Mónica Fuensanta ◽  
José Miguel Martín-Martínez
Keyword(s):  
Phase Separation ◽  
Potential Application ◽  
Viscoelastic Properties ◽  
Gravimetric Analysis ◽  
Scanning Calorimetry ◽  
Adhesion Properties ◽  
Pressure Sensitive Adhesives ◽  
Thermoplastic Polyurethanes ◽  
Pressure Sensitive ◽  
Soft Segments

Thermoplastic polyurethanes (TPUs) were synthetized with blends of poly(propylene glycol) (PPG) and poly(1,4-butylene adipate) (PAd) polyols, diphenylmethane-4,4′-diisocyanate (MDI) and 1,4-butanediol (BD) chain extender; different NCO/OH ratios were used. The structure and viscoelastic properties of the TPUs were assessed by infrared spectroscopy, differential scanning calorimetry, X-ray diffraction, thermal gravimetric analysis and plate-plate rheology, and their pressure sensitive adhesion properties were assessed by probe tack and 180° peel tests. The incompatibility of the PPG and PAd soft segments and the segregation of the hard and soft segments determined the phase separation and the viscoelastic properties of the TPUs. On the other hand, the increase of the NCO/OH ratio improved the miscibility of the PPG and PAd soft segments and decreased the extent of phase separation. The temperatures of the cool crystallization and melting were lower and their enthalpies were higher in the TPU made with NCO/OH ratio of 1.20. The moduli of the TPUs increased by increasing the NCO/OH ratio, and the tack was higher by decreasing the NCO/OH ratio. In general, a good agreement between the predicted and experimental tack and 180° peel strength values was obtained, and the TPUs synthesized with PPG+PAd soft segments had potential application as pressure sensitive adhesives (PSAs).

The effect of plasticization on the properties of poly(urethaneureas) based on oligoether diols, 2,4-toluenediisocyanate, and aromatic diamines

2018 ◽  
Vol 51 (4) ◽  
pp. 337-358 ◽  
Author(s):  
Vasiliy Tereshatov ◽  
Marina Makarova ◽  
Valeriy Senichev ◽  
Zhanna Vnutskikh ◽  
Tamara Oshchepkova ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Polymer Matrix ◽  
Arctic Climate ◽  
The Arctic ◽  
Aromatic Diamines ◽  
Plasticization Effect ◽  
Soft Segments ◽  
Potential Applications ◽  
Partial Crystallization ◽  
First Time

Segmented poly(urethaneureas) (SPUUs) modified with low glass transition temperature chemically inert liquids are of interest due to their controllable properties and potential applications under various environmental conditions. Investigation into the influence of plasticizers on the properties of SPUUs based on oligotetramethyleneoxide diol (polytetramethyleneoxide), oligopropyleneoxide diol (polypropyleneoxide), 2,4-toluenediisocyanate, Ethacure-300, and methylene-bis- o-chloroaniline was conducted. Partial crystallization of polytetramethyleneoxide segments was identified during cooling of some SPUU samples plasticized by di-(2-ethylhexyl)sebacate (DEHS) and tributyl phosphate. Polypropyleneoxide segments did not crystallize under the same conditions. A low crystallization temperature for the amorphous component of the polymer matrix in SPUU (−100°C to 103°C) was attained at a molecular mass ( Mn) of soft segments equal to 2000 g mol−1 and a DEHS concentration equal to 40–45%. A relationship between the mechanical properties of plasticized SPUU, microphase segregation, and dilution of the polymer matrix was found. For the first time, the effect of dilution with plasticizer on the strength of elastomers was considered. The plasticization effect on the mechanical properties of SPUU was investigated in the temperature diapason from 50°C to −70°C. The results of these investigations can be used in various technologies including the design of SPUUs with high elastic properties at temperatures as low as −70°C, typical of extreme conditions of the Arctic climate.

Rheology of Block Copolymers

2007 ◽  
Author(s):  
Chang Dae Han
Keyword(s):  
Mechanical Properties ◽  
Molecular Weight ◽  
Block Copolymers ◽  
Small Angle ◽  
Volume Fraction ◽  
Synthesis Methods ◽  
Chemical Structures ◽  
X Ray Scattering ◽  
Transmission Electron ◽  
Molecular Weight Form

Block copolymer consists of two or more long blocks with dissimilar chemical structures which are chemically connected. There are different architectures of block copolymers, namely, AB-type diblock, ABA-type triblock, ABC-type triblock, and AmBn radial or star-shaped block copolymers, as shown schematically in Figure 8.1. The majority of block copolymers has long been synthesized by sequential anionic polymerization, which gives rise to narrow molecular weight distribution, although other synthesis methods (e.g., cationic polymerization, atom transfer radical polymerization) have also been developed in the more recent past. Owing to immiscibility between the constituent blocks, block copolymers above a certain threshold molecular weight form microdomains (10–50 nm in size), the structure of which depends primarily on block composition (or block length ratio). The presence of microdomains confers unique mechanical properties to block copolymers. There are many papers that have dealt with the synthesis and physical/mechanical properties of block copolymers, too many to cite them all here. There are monographs describing the synthesis and physical properties of block copolymers (Aggarwal 1970; Burke and Weiss 1973; Hamley 1998; Holden et al. 1996; Hsieh and Quirk 1996; Noshay and McGrath 1977). Figure 8.2 shows schematically four types of equilibrium microdomain structures observed in block copolymers. Referring to Figure 8.2, it is well established (Helfand and Wasserman 1982; Leibler 1980) that in microphase-separated block copolymers, spherical microdomains are observed when the volume fraction f of one of the blocks is less than approximately 0.15, hexagonally packed cylindrical microdomains are observed when the value of f is between approximately 0.15 and 0.44, and lamellar microdomains are observed when the value of f is between approximately 0.44 and 0.50. Some investigators have observed ordered bicontinuous double-diamonds (OBDD) (Thomas et al. 1986; Hasegawa et al. 1987) or bicontinuous gyroids (Hajduk et al. 1994) at a very narrow range of f (say, between approximately 0.35 and 0.40) for certain block copolymers. Figure 8.2 shows only one half of the symmetricity about f = 0.5. Transmission electron microscopy (TEM), small-angle X-ray scattering (SAXS), and small-angle neutron scattering (SANS) have long been used to investigate the types of microdomain structures in block copolymers.

Studying the effects of chain extenders chemical structures on the adhesion and mechanical properties of a polyurethane adhesive

2013 ◽  
Vol 19 (6) ◽  
pp. 1949-1955 ◽  
Author(s):  
H. Sheikhy ◽  
M. Shahidzadeh ◽  
B. Ramezanzadeh ◽  
F. Noroozi
Keyword(s):  
Mechanical Properties ◽  
Polyurethane Adhesive ◽  
Chemical Structures ◽  
Chain Extenders

Thermal and mechanical properties of polyisobutylene-based thermoplastic polyurethanes

2013 ◽  
Vol 130 (2) ◽  
pp. 891-897 ◽  
Author(s):  
Pallavi Kulkarni ◽  
Umaprasana Ojha ◽  
Xinyu Wei ◽  
Niraj Gurung ◽  
Kasyap Seethamraju ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Thermal And Mechanical Properties ◽  
Thermoplastic Polyurethanes

Effect of the carbon black content on the thermal, rheological and mechanical properties of thermoplastic polyurethanes

2015 ◽  
Vol 29 (11) ◽  
pp. 1136-1154 ◽  
Author(s):  
Sonia Álvarez-García ◽  
José Miguel Martín-Martínez
Keyword(s):  
Mechanical Properties ◽  
Carbon Black ◽  
Carbon Black Content ◽  
Thermoplastic Polyurethanes

Immobilization of Chitosan on the Plasma-Activated Poly-L-Lactic Acid Film Surface Using Evaporated Acrylic Acid as the Intermediate

2006 ◽  
Vol 49 ◽  
pp. 197-202
Author(s):  
Chih Ling Huang ◽  
Ying Yi Lin ◽  
Jiunn Der Liao
Keyword(s):  
Mechanical Properties ◽  
Cell Growth ◽  
Acrylic Acid ◽  
Film Surface ◽  
Thermal Cracking ◽  
Fibroblastic Cell ◽  
Chemical Structures ◽  
Plla Film ◽  
Growth Assay

Nerve bridging is to suture a biomaterial-made conduit and to overpass the damaged nerve end to end with microsurgery. Poly L-lactide (PLLA) is an excellent biomaterial that has biocompatible, biodegradable and good mechanical properties; it is thus potential to be engineered as nerve conduits and manufactured as scaffolds for nerve tissue replacement. On the other hand, chitosan provides cell affinity and considerably promotes nerves regeneration. This study is to apply plasma processing for PLLA film modification, graft the plasma-modified film with vaporized acrylic acid (AAc) monomers and then immobilize chitosan by amide bonding on the pAAc-grafted surface. This work using plasma-activation and subsequent evaporation of AAc greatly avoids PLLA thermal cracking and remaining the PLLA film in good mechanical properties. Surface morphologies are evaluated by Nano Focus. Electron Spectroscopy for Chemical Analysis (ESCA) and Attenuated Total Reflectance Fourier-Transform Infrared Spectroscopy (ATR-FTIR) are respectively employed for determining elements’ functionalities and chemical structures. Moreover, biological functionalities of the chitosan-immobilized PLLA films are thereafter assessed by antibacterial test and in vitro fibroblastic cell growth assay. The result exhibits that chitosan is immobilized on the modified PLLA films, which is plasma-activated subsequent to the evaporation of AAc. The process does not induce thermal cracking. In vitro fibroblastic cell growth assay on the chitosan-immobilized PLLA films has demonstrated that fibroblast cells on the surface become circular in shape. It decreases cell growth rate and the development of scar tissues, which may thereafter promote the effect of nerve repairing.

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