A spectroscopic study of domain ordering in diacetylene-containing model polyurethanes

Nitzsche, S. A.; Hsu, Shaw Ling; Hammond, Paula T.; Rubner, Michael F.

doi:10.1021/ma00035a015

Cited by 17 publications

(11 citation statements)

References 7 publications

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“…The low intensity of the disorder‐induced bands demonstrated the low amount of defects on the walls of the A‐MWNTs used in this work. The TPU spectrum presents a main feature at 1 620 cm −1 , which is assigned as C = C bond stretching as previously reported 26…”

Section: Resultssupporting

confidence: 70%

Thermoplastic Polyurethane Nanocomposites Produced via Impregnation of Long Carbon Nanotube Forests

Silva¹,

Rodrigues²,

Fantini³

et al. 2010

Macro Materials & Eng

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TPU was infiltrated into vertically aligned, 3.5 mm‐long MWNT forests to produce continuously reinforced anisotropic nanocomposites, and thermomechanical and electrical testing has revealed multifunctionality which shows promise for numerous applications. A 1000% increase in the storage modulus at 70 °C was observed as compared to the neat TPU, and these continuously aligned composites showed electrical conductivity two orders‐of‐magnitude greater (≈1.5 S · cm−1) than randomly aligned composites prepared using CNTs from these forests. The heightened improvement for the continuously reinforced composite appears to be owed to the extremely high aspect ratio of these CNTs and the interconnected network which remains after infiltration. magnified image

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Section: Resultssupporting

confidence: 70%

Thermoplastic Polyurethane Nanocomposites Produced via Impregnation of Long Carbon Nanotube Forests

Silva¹,

Rodrigues²,

Fantini³

et al. 2010

Macro Materials & Eng

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“…It drives the polymer into two phase morphology in which crystalline hard micro domains are hydrogen‐bonded to form larger domains. These hard microdomains form fibrillar, globular, cylindrical, or lamellar structures within a continuous soft matrix and reinforces the soft matrix by acting as physical crosslinking sites depending on the specific segmental composition 13–22. In addition, the intersegmental hydrogen‐bonding capability of the hard segment increases the cohesiveness of the hard domains and association of the hard domains provides additional driving force for phase separation 23–27…”

Section: Introductionmentioning

confidence: 99%

“…These hard microdomains form fibrillar, globular, cylindrical, or lamellar structures within a continuous soft matrix and reinforces the soft matrix by acting as physical crosslinking sites depending on the specific segmental composition. [13][14][15][16][17][18][19][20][21][22] In addition, the intersegmental hydrogen-bonding capability of the hard segment increases the cohesiveness of the hard domains and association of the hard domains provides additional driving force for phase separation. [23][24][25][26][27] Polyurethane is fascinating system to tune its properties and structural variation with its selfassembling morphology.…”

Section: Introductionmentioning

confidence: 99%

Morphology of polyurethanes at various length scale: The influence of chain structure

Mishra

Maiti

2011

J of Applied Polymer Sci

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Micro-structural investigation of polyurethanes (PUs) with different chain structure has been reported. Polarized optical microscopic studies of aliphatic polyurethanes demonstrate the development of micro clusters with increasing hard segment content (HSC) and crystallization. DSC and XRD results support the crystalline and amorphous nature of aliphatic and aromatic PUs, respectively. Self-assembled biphasic morphology is discernible in aliphatic polyurethane while nanometer size domains are observed in aromatic PUs. The dimension of micro-domain has been measured by using AFM and established its size as independent of hard segment content. The self-assembly is greater for higher HSC aliphatic PUs leading to the formation of bigger domain while the meager hydrogen bond formation restricts the domain size of aromatic polyurethanes. Segmented morphology of surface as well as in bulk of aliphatic polyurethanes is evident from SEM and TEM images and grows with increasing HSC. In contrast, homogeneous and amorphous nature has been observed for aromatic PUs. In situ segregation of phases in aliphatic PUs have been captured through light transmittance and optical images which is categorically absent in aromatic polyurethane.

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“…Some researchers have reported some differences in Raman shift frequency and intensity that correspond to the differences in molecular structures for some polydiacetylenes. Nitzsche et al [6] reported the different shapes of both >C=C< and −C≡C− stretching bands of DA-coPUs (PTMO / MDI / HDD) that were prepared by casting using different solvents.…”

Section: Dcs Curves Inmentioning

confidence: 99%

Study on Application of Diacetylene- containing Copolyurethanes (DA-coPUs) coating as strain sensors using Raman Spectroscopy

Sutrisno

Stanford²,

Lovell³

2005

JFA

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A two-phase copolymer DA-coPUs containing of 50% hard-segment has been prepared using a polyoxypropylene-diol with molecular weight of 2000 (Voranol 2000), 4,4 -diphenylmethane diisocyanate (MDI) and 2,4-hexadiyne-1,6-diol (HDD) via a one-shot, bulk polymerization process. Solution of linear, as-prepared DA-coPUs in N,N-Dimethylacetamide (DMAc) was coated onto pre-heated steel beam. Cross polymerization of the DA-coPUs were carried out using heating under nitrogen at 100• C for 5 hours. Deformation micromechanics of the DA-coPUs has been studied using simultaneous 4-point bending testing and Raman spectroscopy. The results showed that the coating has poorer strain-induced Raman band shift factors than that of pure DA-coPUs [1] c 2005 Jurusan Fisika FMIPA ITS

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A spectroscopic study of domain ordering in diacetylene-containing model polyurethanes

Cited by 17 publications

References 7 publications

Thermoplastic Polyurethane Nanocomposites Produced via Impregnation of Long Carbon Nanotube Forests

Thermoplastic Polyurethane Nanocomposites Produced via Impregnation of Long Carbon Nanotube Forests

Morphology of polyurethanes at various length scale: The influence of chain structure

Study on Application of Diacetylene- containing Copolyurethanes (DA-coPUs) coating as strain sensors using Raman Spectroscopy

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