Hard block reduction and synthesis improvements in Odin II

2015 ◽  
Author(s):  
Bo Yan ◽  
Kenneth B. Kent
Keyword(s):  
Hard Block

Effect of Block Molecular Weight on the Mechanical Properties of PA1010-b-PEG Segmented Block Copolymers

2012 ◽  
Vol 512-515 ◽  
pp. 2127-2130
Author(s):  
Li Huo ◽  
Cai Xia Dong
Keyword(s):  
Mechanical Properties ◽  
Molecular Weight ◽  
Block Copolymers ◽  
Microphase Separation ◽  
Soft Segment ◽  
Mechanical Measurements ◽  
Wide Range ◽  
Hard Block ◽  
Higher Temperature ◽  
Hard Segments

The mechanical properties were investigated of a series of PA-PEG thermalplastic elastomer based on PA1010 and polytetramethylene glycol (PEG) with varying hard and soft segment content. Dynamic mechanical measurements of these polymers have carried out over a wide range of temperatures. The block copolymers exhibit three peaks, designated as α, β and γ in the tanδ-temperature curve. The α transition shifts to higher temperature with increasing hard block molecular weight. However, at a constant hard molecular weight, the α transition shifts to higher temperature and the damping increases on increasing the soft segment molecular weight. DMA results show that the block copolymers exhibit a microphase separation structure and both soft and hard segments were found to be crystallizable. The degree of phase separation increases with increasing hard block molecular weight.

Origin of Multiple Melting Endotherms in a High Hard Block Content Polyurethane. 1. Thermodynamic Investigation

2001 ◽  
Vol 34 (26) ◽  
pp. 9059-9068 ◽  
Author(s):  
A. Saiani ◽  
W. A. Daunch ◽  
H. Verbeke ◽  
J.-W. Leenslag ◽  
J. S. Higgins
Keyword(s):  
Thermodynamic Investigation ◽  
Hard Block ◽  
Multiple Melting

An ABA triblock containing a central soft block of poly[2,5-di(n-hexogycarbonyl)styrene] and outer hard block of poly(4-vinylpyridine): synthesis, phase behavior and mechanical enhancement

RSC Advances ◽  
2014 ◽  
Vol 4 (35) ◽  
pp. 18431-18441 ◽  
Author(s):  
Xin Liu ◽  
Rui-Ying Zhao ◽  
Ti-Peng Zhao ◽  
Chen-Yang Liu ◽  
Shuang Yang ◽  
...  
Keyword(s):  
Phase Transformation ◽  
Phase Behavior ◽  
Triblock Copolymer ◽  
Microphase Separation ◽  
Metal Salt ◽  
Hard Block ◽  
Aba Triblock Copolymer

A new ABA triblock copolymer (P4VP-PHCS-P4VP) with strong microphase separation was successfully synthesized and showed phase transformation and mechanical enhancement by blending with metal salt.

scholarly journals Phase Separation and Crystallization in High Hard Block Content Polyurethane Thin Films

2015 ◽  
Vol 48 (15) ◽  
pp. 5358-5366 ◽  
Author(s):  
Long Jiang ◽  
Jia Wu ◽  
Chinemelum Nedolisa ◽  
Alberto Saiani ◽  
Hazel E. Assender
Keyword(s):  
Thin Films ◽  
Phase Separation ◽  
Hard Block

The Effect of Mixed Chain Extender on the Hydrogen Bonding, Thermal and Mechanical Properties of TPUs

2020 ◽  
Vol 1001 ◽  
pp. 16-21
Author(s):  
Ju Jie Sun ◽  
Hai Rui Wang ◽  
Lan Cao ◽  
Tridib K. Sinha
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Hydrogen Bonding ◽  
Thermoplastic Polyurethane ◽  
Chain Extender ◽  
Mixing Ratio ◽  
Thermal And Mechanical Properties ◽  
Elongation At Break ◽  
Chain Extenders ◽  
Hard Block

Chain extender plays a significant role in enhancing the final mechanical properties of thermoplastic polyurethane (TPUs) derived from polytetra methylene etherglycol (PTMG) and 4,4-diphenylmethane diisocyanate (MDI). In this research we focused on the effect that mixed chain extender of ethylene glycol (EG) and 1,4-butanediol (BDO) used has on the phase behavior and morphology of high hard block content TPUs. DSC, FTIR, and mechanical testing were mainly used to characterize the morphology and properties of the TPUs materials. Through this work we were able to show that mixed ratio of different chain extenders had dramatic effects on the properties of the TPUs. After mixing EG and BDO, the degree of hydrogen bonding, melting temperature, tensile strength, tear strength, and hardness of TPUs are all reduced, the glass transition temperature is increased. when the mixing ratio is 1: 1 , the elongation at break is increased to 672% . However, when the mixing ratio is n (EG): n (BDO) = 1: 2, the tensile strength is increased to 29.2 MPa, and the elongation at break is reduced to 353%.

An Embedding Mixture for Electron Microscopic Technique Composed Solely of Maraglas, Araldite and Catalyst

1968 ◽  
Vol 26 ◽  
pp. 242-243
Author(s):  
Dale E. McClendon ◽  
Bernard L. Soloff
Keyword(s):  
Propylene Oxide ◽  
Microscopic Technique ◽  
Electron Microscopic ◽  
Thin Sections ◽  
Low Intensity ◽  
Electron Microscopic Technique ◽  
Hard Block ◽  
The Stability

We have found the following embedding mixture to be useful: Maraglas 655 - 70 ml., Araldite 502 - 30 ml., benzyldimethylamine - 3 ml. The tissue blocks are processed routinely through a 1:3 mixture of propylene oxide: complete embedding mixture. After overnight soaking in this mixture, the tissue blocks are allowed to sink for two hours in capsules loaded with fresh embedding mixture. The capsules are then processed four hours in a 37 - 40° C. oven, followed by three days in a 65° C. oven. This treatment yields a hard block that may be sectioned immediately upon cooling. The thin sections obtained will accept readily any of the staining solutions now available.Elimination of the anhydride hardener used normally in formulations of this sort does not affect the stability of thin sections under a 50 or 75 KV beam (figures 1 and 3), and sections supported on naked grids will withstand a 100 KV beam (figure 2) if carefully irradiated at low intensity before exposure to cross-over conditions.

Hard Block Degradable Polycarbonate Urethanes: Promising Biomaterials for Electrospun Vascular Prostheses

2019 ◽  
Vol 21 (2) ◽  
pp. 376-387 ◽  
Author(s):  
Katharina Ehrmann ◽  
Paul Potzmann ◽  
Claudia Dworak ◽  
Helga Bergmeister ◽  
Magdalena Eilenberg ◽  
...  
Keyword(s):  
Vascular Prostheses ◽  
Hard Block

Spin-Label Investigation of Polyurethane Networks

1974 ◽  
Vol 47 (5) ◽  
pp. 1160-1174
Author(s):  
T. C. Ward ◽  
J. T. Books
Keyword(s):  
Mechanical Properties ◽  
Spin Label ◽  
Amorphous Polymers ◽  
Diphenylmethane Diisocyanate ◽  
Label Technique ◽  
Spin Resonance ◽  
Soft Segments ◽  
Polyurethane Networks ◽  
Hard Block ◽  
Very High

Abstract Two types of polyurethane networks were examined using the spin-label technique. Nitroxide free radicals which are stable under moderate conditions were covalently attached to the network chains of amorphous polymers based on (1) poly(tetramethylene glycol), p,p′-diphenylmethane diisocyanate (MDI), trimethylolpropane, and (2) ethylene glycol, MDI, glycerine. Polymer (1) had very low “hard block” content, polymer (2) a very high content. Mechanical properties and differential thermal analysis measurements were made on polymer (1). Electron spin resonance spectra of the samples were obtained in the unstrained, strained, and swollen states. Large differences in the spectra were observed, depending on chemical composition, temperature, and state of swelling. Transitions from “frozen” to “rapid motion” type of spectra occurred at 70° for polymer (1), at −10° for polymer (1) swollen to equilibrium, and were unobserved up to 150° for polymer (2). Since the nitroxide label was necessarily adjacent to MDI units, was present in very small concentrations, and experienced no alterations in environment as “soft segments” did, then it is suggested that the spin-label technique is a valuable tool for analyzing microstructure of pseudoamorphous systems.

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