Papers by Keyword: Polyurethane (PU)

Paper TitlePage

Authors: Peng Fei Yang
Abstract: Phenyl isocyanate is used to react with 1,3-butanediol at different temperatures. Toluene is used as solvent and 1,4-diazabicyclo[2,2,2]octane is used as catalyst. In-situ FT-IR is used to monitor the reaction to work out rate constant, Arrhenius equation and Eyring equation. The urethane reaction has been found to be a second order reaction, and the rate constant seems different between initial stage and final stage. The activation energy (Ea), activation enthalpy (ΔH) and activation entropy (ΔS) for the urethane reaction of primary hydroxyl group are calculated out, which are 26.4 kJ•mol-1, 23.6 kJ•mol-1 and -186.6 J•mol-1•k-1, respectively. They are very useful to reveal the reaction mechanism.
2223
Authors: Peng Fei Yang
Abstract: Phenyl isocyanate is used to react with 1,2-propanediol in different temperatures. Toluene is used as solvent and triethylamine is used as catalyst. In-situ FT-IR is used to monitor the reaction to work out rate constant, Arrhenius equation and Eyring equation. The urethane reaction has been found to be a second order reaction, and the rate constant seems different between initial stage and final stage. The activation energy (Ea), activation enthalpy (ΔH) and activation entropy (ΔS) for the urethane reaction are calculated out, which are 74.1 kJ•mol-1, 71.3 kJ•mol-1 and -30.5 J•mol-1•k-1, respectively. They are very useful to reveal the reaction mechanism.
131
Authors: Peng Fei Yang
Abstract: Phenyl isocyanate is used to react with 1,3-butanediol at different temperatures. Dimethylformamide is used as solvent. In-situ FT-IR is used to monitor the reaction to work out rate constant, Arrhenius equation and Eyring equation. The urethane reaction has been found to be a second order reaction, and the rate constant seems different between initial stage and final stage. The activation energy (Ea), activation enthalpy (ΔH) and activation entropy (ΔS) for the urethane reaction of primary hydroxyl group are calculated out, which are 90.9 kJ•mol-1, 88.2 kJ•mol-1 and 20.2 J•mol-1•k-1, respectively. They are very useful to reveal the reaction mechanism.
1911
Authors: Peng Fei Yang
Abstract: Phenyl isocyanate is used to react with 3-methyl-1,3-butanediol at different temperatures. Dimethylformamide is used as solvent. In-situ FT-IR is used to monitor the reaction to work out rate constant, Arrhenius equation and Eyring equation. The urethane reaction has been found to be a second order reaction, and the rate constant seems different between initial stage and final stage. The activation energy (Ea), activation enthalpy (ΔH) and activation entropy (ΔS) for the urethane reaction of tertiary hydroxyl group are calculated out, which are 75.2 kJ•mol-1, 72.4 kJ•mol-1 and -44.8 J•mol-1•k-1, respectively. They are very useful to reveal the reaction mechanism.
1743
Authors: Sarojini Swain, Subhendu Bhattacharya, Ram Avatar Sharma, Lokesh Chaudhari
Abstract: Hydroxyl modified multi-walled carbon nanotubes (OH-MWCNT)/ polyurethane (PU) and graphene nanosheets (GNS)/PU composites were prepared by dispersing the OH-MWCNT and GNS at different wt % in to the PU matrix. It was found that the electrical percolation threshold of the GNS/PU composite is much higher compared to that of OH-MWCNT/PU and also the electrical conductivity of the OH-MWCNT/PU composite is higher than the GNS/PU composite in the same level of filler content. This may be due to the two composites having different electrical conduction mechanisms: The OH-MWCNT/PU composite represents a three dimensional conduction system while, the GNS/PU composite represents a two dimensional conduction system. The improvement in the electrical conductivity with the incorporation of GNS as a filler in the composite is far lower than what theoretically expected. It is also observed that the tensile strength of the OH-MWCNT/PU composite is higher compared to the GNS/PU in the same level filler content.
781
Authors: Yun Lu, Wei Jia Li, Yun Peng Li, Jian Feng Li
Abstract: The polyurethane buffer is widely used in mechanical industry, intelligent manufacturing, internal combustion engine industry and etc.. The parameter design of the polyurethane buffer is often based on empirical formula with which it usually can not obtain the optimal parameter. This paper aims at studying the process of the buffer and optimizing its parameter. Firstly, the result of compression and shear tests of the polyurethane material is compared with simulation result to validate the simulation method is reasonable. Then buffers of different sizes with practical condition were simulated. During the simulation, this paper researched the maximum deceleration of the mass block in models with different sizes of polyurethane buffers. Lastly, the size of the buffer with minimum volume which is agreed with the request of the maximum deceleration of the mass block is obtained by data handling based on the simulation result, above on which a database was built.
182
Authors: Cheng Wei Hou, Zhi Jiang Cai
Abstract: In this paper, electro-active actuator made with cellulose and polyurethane blend film is prepared, which can show high bending displacement in the air with room humidity condition. To fabricate this actuator, cotton cellulose was dissolved into a N,N-dimethylacetamide (DMAc) and lithium chloride (LiCl) solvent system. Polyurethane prepared by poly[di(ethylene glycol) adipate] and hexamethylene diisocyanate (HDI) was mixed with DMAc cellulose solution by stirring. The mixed solution was cast to form a film followed by depositing thin gold electrode on both sides of the film. The actuator was actuated under AC voltage at an ambient condition by changing the actuation voltage, frequency and time. The actuator revealed a large bending displacement under low activation voltage, low electrical power consumption and good durability at room condition. This cellulose- polyurethane blend actuator is suitable for dry and durable actuator and promising for many biomimetic applications in foreseeable future.
40
Authors: Anežka Lengálová, Petr Slobodian, Robert Olejnik, Pavel Riha
Abstract: A sensing element made of conductive composite created by an entangled network of electrically conductive carbon nanotubes embedded in polyurethane was used for simultaneous measurements of the pressure between the shoe and floor as well as the extension of the leg at the knee joint during marching. The results recorded as sensor resistance change show reasonable reversibility of the basic sensor characteristics, which gives potential for practical applications.
43
Authors: Hong Jun Huang, Kang Wang, Jian Jiang Wang, Guo Shun Wan, Lei Jiang
Abstract: A series of spongy foams based on polyurethane (PU) modified by polyisobutylene (PIB) were prepared. The spongy foams with different PIB content were investigated. The results showed that initial adhesion increased with the increment of PIB content, and gained the highest value when the content reached to 30%; FTIR suggested the formation of PU foam modified by PIB; the density also increased with the increasing content of PIB.
314
Authors: Hong Jun Huang, Wang Kang, Guo Shun Wan, Jiang Lei
Abstract: A series of interpenetrating polymer networks (IPN) spongy foams based on polyurethane (PU) and epoxy resin (EP) were prepared by a simultaneous polymerization technique. The PU/EP IPN spongy foams with different epoxy content were investigated. The results showed that initial adhesion increased with the increment of EP content, and gained the highest value when the content reached to 20%; FTIR suggested the formation of PU/EP IPN; the density also increased with the increasing content of epoxy; the highest degree of uniformity in bubbles were observed in foams with 20% content of epoxy resin.
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