Synthesis and Characterization of Biomedical Aliphatic Polyurethane Material

2014 ◽  
Vol 809-810 ◽  
pp. 520-526
Author(s):  
Rong Zhu ◽  
Zong Rui Zhang ◽  
Ming Bei Zhu ◽  
Xin Yu Wang
Keyword(s):  
Mechanical Properties ◽  
Hard Segment ◽  
Soft Segment ◽  
Molar Ratio ◽  
Dibutyltin Dilaurate ◽  
Biomedical Material ◽  
Prepared Material ◽  
The Relationship ◽  
Poly Carbonate

Biomedical transparent poly(carbonate-urethane) elastomers were synthesized by melting pre-polymer method, using 4,4’-methylenebis (cyclohexyl isocyanate)(H12MDI) and chain extender (butadiene)(BDO) as hard segment, poly(1,6-hexanediol) carbonate diols(PCDL) as soft segment, and dibutyltin dilaurate as catalyst.The effects of molar ratio of the reactants on mechanical properties of PCU were studied and the relationship between micro-phase separation structure and properties was analyzed by the contact angle determination, total reflection fourier transform infrared spectrography(ATR-FTIR), differential scanning calorimeter(DSC),gel permeation chromatograph (GPC), mechanical property test. The comparative analysis was made between the prepared material and commercial medical polyurethane materials, showing the prepared poly(carbonate-urethane) elastomers was better in mechanical properties. As a elastic biomedical material, it has a great potential for developments and applications in biomedical materials.

Structural Characterization of Segmented Polyurethanes by Small Angle Neutron Scattering

2001 ◽  
Vol 707 ◽  
Author(s):  
Loren I. Espada ◽  
Joseph T. Mang ◽  
E. Bruce Orler ◽  
Debra A. Wrobleski ◽  
David A. Langlois ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Neutron Scattering ◽  
Small Angle ◽  
Small Angle Neutron Scattering ◽  
Hard Segment ◽  
Microphase Separation ◽  
Soft Segment ◽  
Chain Scission ◽  
Segmented Polyurethanes

ABSTRACTThe beneficial mechanical properties of segmented polyurethanes derive from microphase separation of immiscible hard and soft segment-rich domains at room temperature. We are interested in the structure of the domains, how these are affected by hydrolytic aging, and how the structure is modified by low molecular weight plasticizers. To assessed the distribution of the plasticizer in polyurethane, we did small-angle neutron scattering measurements on mixtures of 23% hard segment poly(esterurethane) with different amounts of either non-deuterated or deuterated plasticizer. We analyzed the results using a simple model in which the contrast, Δ=H-, between the hard and soft segment-rich domains is varied by the amount of deuterated or hydrogenated plasticizer, using the fact that I(Q) ∼ Δ2. The result demonstrated that the plasticizer is largely associated with the soft segment rich domains. The structure of PESU with the chain extender of the hard segment was assessed after aging under hydrolytic conditions. The results show that the microphase structure coarsens and segregates and that the hard and soft segments segregated as a result of the loss of constraints from hydrolytic soft segment chain scission. The results on plasticizer distribution and the effects of hydrolytic aging give insight on the loss of mechanical properties that occur in each case.

Structural Characterization of Segmented Polyurethanes by Small Angle Neutron Scattering

2001 ◽  
Vol 710 ◽  
Author(s):  
Loren I. Espada ◽  
Joseph T. Mang ◽  
E. Bruce Orler ◽  
Debra A. Wrobleski ◽  
David A. Langlois ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Neutron Scattering ◽  
Small Angle ◽  
Small Angle Neutron Scattering ◽  
Hard Segment ◽  
Microphase Separation ◽  
Soft Segment ◽  
Chain Scission ◽  
Segmented Polyurethanes

ABSTRACTThe beneficial mechanical properties of segmented polyurethanes derive from microphase separation of immiscible hard and soft segment-rich domains at room temperature. We are interested in the structure of the domains, how these are affected by hydrolytic aging, and how the structure is modified by low molecular weight plasticizers. To assessed the distribution of the plasticizer in polyurethane, we did small-angle neutron scattering measurements on mixtures of 23% hard segment poly(esterurethane) with different amounts of either non-deuterated or deuterated plasticizer. We analyzed the results using a simple model in which the contrast, Δρ = ρH Š ρ, between the hard and soft segment-rich domains is varied by the amount of deuterated or hydrogenated plasticizer, using the fact that I(Q) ∼ Δρ2. The result demonstrated that the plasticizer is largely associated with the soft segment rich domains. The structure of PESU with the chain extender of the hard segment was assessed after aging under hydrolytic conditions. The results show that the microphase structure coarsens and segregates and that the hard and soft segments segregated as a result of the loss of constraints from hydrolytic soft segment chain scission. The results on plasticizer distribution and the effects of hydrolytic aging give insight on the loss of mechanical properties that occur in each case.

scholarly journals Nano/micro-mechanical and tribological characterization of Ar, C, N, and Ne ion-implanted Si

2010 ◽  
Vol 25 (5) ◽  
pp. 880-889 ◽  
Author(s):  
Zhi-Hui Xu ◽  
Young-Bae Park ◽  
Xiaodong Li
Keyword(s):  
Mechanical Properties ◽  
Tribological Properties ◽  
Crystalline Silicon ◽  
Semiconductor Industry ◽  
Damage Mechanism ◽  
Mechanical And Tribological Properties ◽  
Tribological Characterization ◽  
The Relationship ◽  
Ion Implanted

Ion implantation has been widely used to improve the mechanical and tribological properties of single crystalline silicon, an essential material for the semiconductor industry. In this study, the effects of four different ion implantations, Ar, C, N, and Ne ions, on the mechanical and tribological properties of single crystal Si were investigated at both the nanoscale and the microscale. Nanoindentation and microindentation were used to measure the mechanical properties and fracture toughness of ion-implanted Si. Nano and micro scratch and wear tests were performed to study the tribological behaviors of different ion-implanted Si. The relationship between the mechanical properties and tribological behavior and the damage mechanism of scratch and wear were also discussed.

The Identification and Characterization of Two Crystal forms in MDI/BDO Based Polyurethanes by Stem, TEM and Microdiffraction

1982 ◽  
Vol 40 ◽  
pp. 674-675
Author(s):  
Robert M. Briber
Keyword(s):  
Hard Segment ◽  
Soft Segment ◽  
Random Copolymer ◽  
Crystal Forms ◽  
X Ray ◽  
Dsc Studies ◽  
Considerable Research ◽  
Identification And Characterization ◽  
Butane Diol

Polyurethanes based on 4,4'-diphenylmethane diisocyanate (MDI), 1,4-butane diol (BDO) and polypropylene oxide diol (PPO) form a segmented random copolymer which phase separates into hard and soft segment domains. The morphology of the hard segment (MDI/BDO) domains has been the object of considerable research because of the large influence of these domains on the mechanical properties of the material. A number of models based on wide and small angle x-ray and DSC studies ranging from highly ordered crystallites to paracrystalline domains have been proposed. In this study STEM and TEM imaging coupled with microdiffraction has revealed the presence of two distinct crystal structures with different morphologies.

scholarly journals One Pot Synthesis and Characterization of Palladium [Pd(Anil-Tolu)4(H2O)2]by insitu Method

2019 ◽  
Vol 9 (2S4) ◽  
pp. 273-276
Keyword(s):  
Metal Complex ◽  
Fourier Transforms ◽  
Molar Ratio ◽  
Nitrate Hexahydrate ◽  
X Ray Diffraction ◽  
One Pot ◽  
Prepared Material ◽  
Palladium Nitrate ◽  
Fourier Transforms Infrared Spectroscopy

The insitu synthesis of Schiff base metal complex using p-toluedine (p-tolu), p-anisaldehyde (p-anisal) as starting materials with Palladium nitrate hexahydrate (Pd(NO3)2.6H2O) as a metal precursor in the molar ratio (1:1:1 M) at room temperature. The prepared metal complex is washed with several times with ethanol and boiled water for the removal of un-reacted materials completely. To confirm the prepared material by the following characterization like UV-visible spectroscopy, Fourier Transforms Infrared spectroscopy, X-ray diffraction pattern and Cyclic Voltammetry.

EFFECT OF INCREASING NCO/OH MOLAR RATIO ON THE CHEMICAL AND MECHANICAL PROPERTIES OF ISOCYANATE TERMINATED POLYURETHANE PREPOLYMER DERIVED FROM BIO-MASS

2016 ◽  
Vol 2 (2) ◽  
pp. 78-82
Author(s):  
K. Rathika ◽  
S. Begila David
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Castor Oil ◽  
Hard Segment ◽  
Molar Ratio ◽  
Curing Time ◽  
Percent Elongation ◽  
Hard Segment Content ◽  
Polyurethane Film ◽  
Polyurethane Prepolymer

The study deals the effect of increasing NCO/OH molar ratio on the physico-mechanical properties of isocyanate terminated polyurethane prepolymer. The prepolymer was prepared using castor oil and toluene-2,4-diisocyanate. The NCO/OH molar ratio has been varied from 1.6 to 2.0. The formation of the prepolymer was confirmed by UV and FTIR spectroscopy. The results reveal that the curing time of the prepolymer decreased with increase in NCO/OH molar ratio. When NCO/OH molar ratio increased, the tensile strength of the polyurethane film increased, while percent elongation decreased due to increase in hard segment content.

scholarly journals Characterization of Butanediol-Alginate Ester as Candidate of Hemodialysis Membrane

2015 ◽  
Vol 15 (2) ◽  
pp. 146-154 ◽  
Author(s):  
Choirul Amri ◽  
Mudasir Mudasir ◽  
Dwi Siswanta ◽  
Roto Roto
Keyword(s):  
Mechanical Properties ◽  
Protein Adsorption ◽  
Platelet Adhesion ◽  
Membrane Surface ◽  
Molar Ratio ◽  
And Performance ◽  
Hemodialysis Membrane ◽  
Better Than ◽  
Membrane Mechanical Properties

An ester of butanediol-alginate has been studied as a possible hemodialysis membrane. With 1,4-butanediol molar ratio of 0.1, 0.5, and 1.0, it showed that the membrane mechanical properties, stability, protein adsorption, platelet adhesion and performance for urea and creatinine clearance are better than that of unmodified alginate. The increase in 1,4-butanediol molar ratio causes hemodialysis ratio to improve, and causes protein adsorption and platelet adhesion at the membrane surface to decrease. In the case of protein adsorption and platelet adhesion, the membrane with the molar ratio of 1.0 has better hemocompatibility properties. In the hemodialysis test for 4 h, using 2.742 mg cm-2 h-1 of urea and 0.058 mg cm-2 h-1 of creatinine flux, this membrane showed that 48.5% of urea and 44.2% of creatinine were cleaned.

Characterization of Al2O3-Al2TiO2 Ceramic Composites: Effects of Sintering Parameters on the Properties

2018 ◽  
Vol 912 ◽  
pp. 118-123 ◽  
Author(s):  
Manuel Fellipe Rodrigues Pais Alves ◽  
Caio Marcelo Felbinger Azevedo Cossu ◽  
Roberto de Oliveira Magnago ◽  
Alfeu Saraiva Ramos ◽  
Claudinei dos Santos
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Relative Density ◽  
Ceramic Composites ◽  
Molar Ratio ◽  
X Ray Diffraction ◽  
Crystalline Phases ◽  
Temperature Ranges ◽  
Distinct Temperature

This study aims to evaluate the effects of sintering parameters in crystalline phases, microstructure and mechanical properties of composites obtained through the Al2O3-TiO2 ceramic system. Cylindrical specimens, containing molar ratio of 3 Al2O3: 1 TiO2, were uniaxially pressed at 100 MPa. The applied sintering parameters were varied in five distinct temperature ranges (1300°C, 1400°C, 1500°C, 1575°C or 1600°C) for 2h and 1600°C for 10h. After sintering, samples were characterized by relative density, X-ray diffraction, scanning electron microscopy and mechanical properties (hardness and fracture toughness). After sintering the results point to a microstructure with grains near to 2.5mm, independent of the present phases and crystalline phases composed of: Al2O3 rhombohedral, TiO2 tetragonal e Al2TiO5 orthorhombic. The specimens sintered at 1600°C-10h feature densification 30% higher them the ones sintered at 1300°C-2h, reaching a density higher than 85% of theoretical density. The composite presents hardness higher than 1000HV and fracture toughness upper than 2.2MPam1/2. The better results for the mechanical properties were found in the composites sintered at 1600°C-10h, that showed a bigger relative density than all analyzed specimens, and only phases of Al2O3 and Al2TiO5 could be found, what means that all TiO2 was consumed in the sintering of the new composite.

Study on Pore Structure Characterization of Concrete at Different Ages by Thermoporometry

2013 ◽  
Vol 539 ◽  
pp. 178-183 ◽  
Author(s):  
Zheng Wu Jiang ◽  
Zi Long Deng ◽  
Nan Zhang
Keyword(s):  
Mechanical Properties ◽  
Mechanical Property ◽  
High Strength Concrete ◽  
High Strength ◽  
Structure Characterization ◽  
Strength Concrete ◽  
20 Nm ◽  
The Relationship ◽  
Curing Age

In this paper, pore structures and their changes of ordinary-strength concrete and high-strength concrete at different curing ages of 3, 28, 90 days were studied using thermoporometry, and the results were compared with those from MIP and NAD. The relationship between micro pores and porosity of concrete and its macroscopic properties was also studied. The results indicate that, compared to MIP, thermoporometry can characterize the features of pores with the diameter smaller than 100 nm in concrete accurately. The differences of macroscopic mechanical properties of concretes can be explained using the changes of their pore size distribution. After curing age of 28 days, the amount of pores with the diameter higher than 20 nm in high strength concrete changes little, but it decreases gradually in ordinary strength concrete. And pores with diameter smaller than 20 nm in concrete have little influence on the macroscopic mechanical property of concrete.

Synthesis and Characterization of PLA-Based Aliphatic-Aromatic Copolyesters: Effect of Diols

2008 ◽  
Vol 55-57 ◽  
pp. 785-788
Author(s):  
M. Namkajorn ◽  
Atitsa Petchsuk ◽  
Mantana Opaprakasit ◽  
Pakorn Opaprakasit
Keyword(s):  
Mechanical Properties ◽  
Molecular Weight ◽  
Lactic Acid ◽  
Chemical Structure ◽  
Molar Ratio ◽  
Synthesis And Characterization ◽  
Polycondensation Reaction ◽  
Dimethyl Terephthalate ◽  
Aromatic Species

PLA-based aliphatic aromatic copolyesters have been synthesized and characterized in order to incorporate the degradability of PLA and good mechanical properties of aromatic species. Synthesis of the copolymers was conducted by polycondensation of lactic acid with dimethyl terephthalate (DMT) and various diols using stannous(II) octoate as a catalyst. Three types of diols with different methylene lengths were employed, i.e., ethylene glycol (EG), propylene glycol (PG) and 1, 4-butanediol (BD). Effects of diols and comonomer molar ratio on the extent of polycondensation reaction and molecular weight of the resulting copolymers were investigated. Diacids and diol ratios of L-lactic acid (LLA), dimethyl terephthalate (DMT) and diol of 1/1/2, 1/2/4 and 2/1/2 were employed. Characterization of chemical structure, molecular weight and thermal and physical properties of the resulting copolymers were conducted by FTIR, NMR, and DSC.

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