scholarly journals Hydrogen Bonding-Mediated Microphase Separation during the Formation of Mesoporous Novolac-Type Phenolic Resin Templated by the Triblock Copolymer, PEO-b-PPO-b-PEO

Materials ◽  
2013 ◽  
Vol 6 (11) ◽  
pp. 5077-5093 ◽  
Author(s):  
Wei-Cheng Chu ◽  
Shih-Fan Chiang ◽  
Jheng-Guang Li ◽  
Shiao-Wei Kuo
Molecules ◽  
2021 ◽  
Vol 26 (15) ◽  
pp. 4705
Author(s):  
Boer Liu ◽  
Xi Chen ◽  
Glenn A. Spiering ◽  
Robert B. Moore ◽  
Timothy E. Long

This work reveals the influence of pendant hydrogen bonding strength and distribution on self-assembly and the resulting thermomechanical properties of A-AB-A triblock copolymers. Reversible addition-fragmentation chain transfer polymerization afforded a library of A-AB-A acrylic triblock copolymers, wherein the A unit contained cytosine acrylate (CyA) or post-functionalized ureido cytosine acrylate (UCyA) and the B unit consisted of n-butyl acrylate (nBA). Differential scanning calorimetry revealed two glass transition temperatures, suggesting microphase-separation in the A-AB-A triblock copolymers. Thermomechanical and morphological analysis revealed the effects of hydrogen bonding distribution and strength on the self-assembly and microphase-separated morphology. Dynamic mechanical analysis showed multiple tan delta (δ) transitions that correlated to chain relaxation and hydrogen bonding dissociation, further confirming the microphase-separated structure. In addition, UCyA triblock copolymers possessed an extended modulus plateau versus temperature compared to the CyA analogs due to the stronger association of quadruple hydrogen bonding. CyA triblock copolymers exhibited a cylindrical microphase-separated morphology according to small-angle X-ray scattering. In contrast, UCyA triblock copolymers lacked long-range ordering due to hydrogen bonding induced phase mixing. The incorporation of UCyA into the soft central block resulted in improved tensile strength, extensibility, and toughness compared to the AB random copolymer and A-B-A triblock copolymer comparisons. This study provides insight into the structure-property relationships of A-AB-A supramolecular triblock copolymers that result from tunable association strengths.


2002 ◽  
Vol 124 (29) ◽  
pp. 8599-8604 ◽  
Author(s):  
Koji Yamauchi ◽  
Jeremy R. Lizotte ◽  
David M. Hercules ◽  
Matthew J. Vergne ◽  
Timothy E. Long

2019 ◽  
Vol 52 (5) ◽  
pp. 410-431 ◽  
Author(s):  
Xun Lu ◽  
Min Xu ◽  
Ye-ming Sheng ◽  
Zhi-peng Li ◽  
Han-mo Li

It is urgent for polyurethane (PU) damping materials to broaden the effective damping range. Based on the designability of PU, this study is focused on the role of long dangling chain, wherein prepared by the reaction of polyethylene glycol monomethyl ether with toluene-2,4-diisocyanate. Notably, the introduction of long dangling chain not only makes the dangling chain longer and enhances the intermolecular interaction but also equips the dangling chain with strong polar carbamate group, bringing about more excellent compatibility of the soft and hard segments and lower degree of microphase separation under the condition of hydrogen bonding. The results show that the damping performance increases with the synergistic effect of significant hydrogen bonding and decreased degree of microphase separation, and the effective damping temperature range (tan δ ≥ 0.3) can exceed 150°C (−50°C to 100°C). Simultaneously, the addition of long dangling chains endows PU with self-healing property, the self-healing rate of system reaches maximum 70% with shore A hardness of 15 because of the synergistic effect above with the addition of 60% dangling chain, which extends the service life of PU damping materials.


RSC Advances ◽  
2014 ◽  
Vol 4 (35) ◽  
pp. 18431-18441 ◽  
Author(s):  
Xin Liu ◽  
Rui-Ying Zhao ◽  
Ti-Peng Zhao ◽  
Chen-Yang Liu ◽  
Shuang Yang ◽  
...  

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.


Polymer ◽  
2002 ◽  
Vol 43 (8) ◽  
pp. 2479-2487 ◽  
Author(s):  
Mei-Wen Huang ◽  
Shiao-Wei Kuo ◽  
Hew-Der Wu ◽  
Feng-Chih Chang ◽  
Su-Yun Fang

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