Synthesis, characterization, and rubber elasticity of end-linked poly(tetrahydrofuran) elastomer

Jong, Lei; Stein, Richard S.

doi:10.1021/ma00009a031

Cited by 21 publications

(12 citation statements)

References 14 publications

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“…Small angle neutron scattering (SANS) studies have revealed that defects are still present in these networks upon swelling. [21][22][23][24][25][26][27] A recent approach by Sakai and coworkers 28 utilized 4-arm star-shaped polymers to reduce network defects and form highly elastic, remarkably homogeneous hydrogels. 29 They achieved this through the use of tetra-arm PEG macromers that cross-link through activated-ester chemistry.…”

Section: Introductionmentioning

confidence: 99%

SANS study of highly resilient poly(ethylene glycol) hydrogels

et al. 2014

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Polymer networks are critically important for numerous applications including soft biomaterials, adhesives, coatings, elastomers, and gel-based materials for energy storage. One long-standing challenge these materials present lies in understanding the role of network defects, such as dangling ends and loops, developed during cross-linking. These defects can negatively impact the physical, mechanical, and transport properties of the gel. Here we report chemically cross-linked poly(ethylene glycol) (PEG) gels formed through a unique cross-linking scheme designed to minimize defects in the network. The highly resilient mechanical properties of these systems (discussed in a previous publication1), suggests that this cross-linking technique yields more homogeneous network structures. Four series of gels were formed based on chains of 35,000 g/mol, (35K), 12,000 g/mol (12K) g/mol, 8,000 g/mol (8K) and 4,000 g/mol (4K) PEG. Gels were synthesized at five initial polymer concentrations ranging from 0.077 g/mL to 0.50 g/mL. Small-angle neutron scattering (SANS) was utilized to investigate the network structures of gels in both D2O and d-DMF. SANS results show the resulting network structure is dependent on PEG length, transitioning from a more homogeneous network structure at high molecular weight PEG to a two phase structure at the lowest molecular weight PEG. Further investigation of the transport properties inherent to these systems, such as diffusion, will aid to further confirm the network structures.

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Section: Introductionmentioning

confidence: 99%

SANS study of highly resilient poly(ethylene glycol) hydrogels

et al. 2014

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“…The resulting model networks are considered more well‐defined than typical sulfur or peroxide vulcanized rubbers and often possess better mechanical properties due to the presence of fewer dangling ends 13,14. Crosslinking telechelic oligomers to form model networks was previously accomplished with polysiloxanes via hydrosilation of vinyl‐terminated and SiH‐terminated oligomers,15–21 but other efforts involve telechelic polyethers,22–24 polyisobutylenes,25 polyurethanes,26 and polyimides 27…”

Section: Introductionmentioning

confidence: 99%

Novel Michael Addition Networks Containing Poly(propylene glycol) Telechelic Oligomers

Mather

Miller

Long

2006

Macro Chemistry & Physics

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Summary: Poly(propylene glycol) oligomers with molecular weights ranging from 1 000 to 8 000 g · mol−1 were end‐functionalized with acetoacetate groups and subsequently crosslinked using carbon‐Michael addition with PEG diacrylate. Gel fraction analysis, DMA, TGA, tensile, and swelling measurements were utilized to characterize the networks. The thermomechanical properties of the networks were analyzed with respect to the molecular weight between crosslink points (Mc) and the critical molecular weight for entanglement (Me). Sampling experiments during crosslinking revealed the evolution of molecular weight with time and monomer conversion. Kinetic analyses of the Michael additions were performed using 1H NMR spectroscopy, and the influence of basic catalyst and concentration was elucidated.Synthesis of acetoacetate networks from acetoacetate‐functionalized PPG using DBU as a basic catalyst.magnified imageSynthesis of acetoacetate networks from acetoacetate‐functionalized PPG using DBU as a basic catalyst.

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“…[2] Values of the average molar mass of chains between crosslinks, M c , were calculated using the standard relationship: The value of the interaction parameter x ¼ 0.43, required to interpret the swelling equilibrium results in toluene, was available in the literature.…”

Section: Swelling Resultsmentioning

confidence: 99%

“…[2,10 -12] The details of the procedures of synthesis are as follows: [2,10] triflic anhydride of 2.5 mL was added to 200 mL of distilled THF. [2,10 -12] The details of the procedures of synthesis are as follows: [2,10] triflic anhydride of 2.5 mL was added to 200 mL of distilled THF.…”

Section: Synthesis Of Hydroxyl-terminated Polymermentioning

confidence: 99%

Sol–Gel Condensations to Form Polytetrahydrofuran Networks and Their Elastomeric Behavior

Hassan

Abdel-Sadek

Beaucage

et al. 2004

Journal of Macromolecular Science, Part A

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A cationic ring-opening polymerization was used to prepare hydroxyl-terminated polytetrahydrofuran (PTHF) [ -(CH 2 ) 4 O -] having a number-average molecular weight of 20,700 g mol 21 , and a relatively narrow molecular weight distribution. Elastomeric tetrafunctional networks were prepared by hydrolysis-condensation reactions on this polymer and on two others that had been commercially obtained. The synthesis was carried out at 608C with 3-isocyanatopropyltriethoxysilane as an end-capping molecule and Sn-octoate as a catalyst. Completeness of the end-capping reaction was followed by infrared absorption spectroscopy, which showed gradual decreases of peaks at 2270.7 and 3475 cm 21 from the disappearances of isocyanato and hydroxyl groups, respectively, and the appearance of a peak at 3350 cm 21 from newly formed NH groups. Analysis of the kinetic data suggest that the -NCO, -OH, and -NH -peaks tend to exhibit first-order kinetics at the beginning of the reaction and 1 reach asymptotic values at extended times. The elastomers thus obtained were studied with regard to their equilibrium swelling in toluene at 258C, and their stress -strain isotherms in elongation. For some of the samples, high elongations seemed to bring about highly desirable strain-induced crystallization, as evidenced by upturns in the modulus. Swelling of these samples with increasing amounts of the non-volatile diluent dibutyl phthalate caused the upturns to gradually disappear, proving that they did indeed result from strain-induced crystallization rather than limited chain extensibility.

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Synthesis, characterization, and rubber elasticity of end-linked poly(tetrahydrofuran) elastomer

Cited by 21 publications

References 14 publications

SANS study of highly resilient poly(ethylene glycol) hydrogels

SANS study of highly resilient poly(ethylene glycol) hydrogels

Novel Michael Addition Networks Containing Poly(propylene glycol) Telechelic Oligomers

Sol–Gel Condensations to Form Polytetrahydrofuran Networks and Their Elastomeric Behavior

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