The Effect of Chain Length of Polyethylene Glycol on Properties of Castor Oil Based Polyurethane Elastomers

Bharadwaj, Vishal; Somani, Keyur; Kansara, Sujata

doi:10.1081/ma-120006522

Cited by 27 publications

(11 citation statements)

References 13 publications

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“…The diffusion coefficient D decreased as the MW of the PEG chains increased (Tables 3 and 4), in agreement with previous works on PEG-based hydrogels (34,38). Similar results were reported also by Brazel and Peppas (33) for some cross-linked poly(2-hydroxyethyl methacrylate-co-methyl methacrylate) and poly(vinyl alcohol) hydrogels.…”

Section: Analysis Of the Water Diffusion Processsupporting

confidence: 92%

“…A possible explanation for D decrease with MW of PEG chains may consists in the increasing semicrystalline character. However, this explanation seems not to cover all data, for example those of Bharadwaj et al (38), who found the same tendency for PEGs with molecular weights of 200, 400, and 600 Da that are not semicrystalline at room temperature. The D was also affected by the functionality of the cross-linking agent, but in a lesser extent than by the MW of the PEG chains.…”

Section: Analysis Of the Water Diffusion Processmentioning

confidence: 75%

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Swelling and Diffusion Characteristics of Hydrogels Synthesized from Diepoxy-terminated Poly(ethylene glycol)s and Aliphatic Polyamines

2010

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Ⅺ Hydrogels from diepoxy-terminated poly(ethylene glycol)s (PEG) of approximate molecular weights 600, 1,000, 2,000, and 4,000 Da and aliphatic polyamines with different numbers of amine hydrogen atoms (ethylene diamine, diethylenetriamine, triethylenetetramine, tris(2-aminoethyl) amine) in various combinations were synthesized and several means to adjust their water absorption were investigated. It was shown that the equilibrium swelling degree (ESD) can be tuned by varying the cross-linking agent functionality and molecular weight (MW) of the PEG precursor, by either employing single components or mixtures of polyamines or PEG oligomers. The ESD was also influenced by the reaction time and concentration of oligomer in feed.Further investigation of the swelling characteristics and water diffusion in the hydrogels synthesized revealed that the semicrystalline character of the xerogels, influenced mainly by the functionality of the cross-linking agent, PEG molecular weight, and degree of perfection of the network, was the main factor affecting the diffusion coefficient and transport mechanism.

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Section: Analysis Of the Water Diffusion Processsupporting

confidence: 92%

Section: Analysis Of the Water Diffusion Processmentioning

confidence: 75%

Swelling and Diffusion Characteristics of Hydrogels Synthesized from Diepoxy-terminated Poly(ethylene glycol)s and Aliphatic Polyamines

2010

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“…Addition of polyisocyanate with aromatic monomer as well as short polyol chains increases the rigidity of the PU backbone which affects the mechanical properties such as Young's modulus. On the contrary, addition of long aliphatic monomer units, most often as part of the polyol, has the opposite affect and allows the PU to have more rubbery characteristics (Yoshida et al, 1990, Bharadwaj et al, 2002. However, addition of too many aromatic or aliphatic units can produce material that is too brittle or rubbery in character for use.…”

Section: Polyurethane (Pu)mentioning

confidence: 96%

The Effect of Plant Source on the Properties of Lignin-Based Polyurethanes

2018

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This work increases our understanding of the effect of plant source on the mechanical and morphological properties of lignin-based polyurethanes (PUs). Lignin is a polymer that is synthesized inside the plant cell wall and can be used as a polyol to synthesize PUs. The specific aromatic structure of the lignin is heavily reliant on the plant source from which it is extracted. These results show that the mechanical properties of ligninbased PUs differ based on lignin's plant source. The morphology of lignin-based PUs was examined using atomic force microscopy and scanning electron microscopy and the mechanical properties of lignin-based PU samples were measured using dynamic mechanical analysis and shore hardness (Type A). The thermal analysis and morphology studies demonstrate that all PUs prepared form a multiphase morphology. In these PUs, better mixing was observed in the wheat straw lignin PU samples leading to higher moduli than in the hardwood lignin and softwood lignin PUs whose morphology was dominated by larger aggregates. Independent of the type of the lignin used, increasing the fraction of lignin increased the rigidity of PU. Among the different types of lignin studied, PU with wheat straw soda lignin exhibited storage moduli ~2-fold higher than those of PUs incorporating other lignins. This study also showed that during synthesis all hydroxyl groups in the lignin are not available to react with isocyanates, which alters the number of cross-links formed within the PU and impacts the mechanical properties of the material.

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“…The effect of chain length of polyethylene glycol on membrane permeability has been investigated by Bharadwaj et al [81]. The diffusion coefficient and sorption of PU elastomer, from castor-oil-based polyol, polyethylene glycol (PEG) of varying molecular weight (200, 400 and 600) and toluene diisocyanate, were found to decrease with an increase in chain length of PEG.…”

Section: Effect Of the Hydrophilic Segmentmentioning

confidence: 99%

Segmented shape memory polyurethane and its water vapor transport properties

Mondal¹,

Hu²

2006

Designed Monomers and Polymers

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Abstract-An attempt has been made to review the influences of different structural factors on physical and water vapor transport properties of segmented shape memory polyurethane (SPU) for breathable textile, biomedical and many other industrial applications. The differences between ordinary, segmented and segmented shape memory polyurethanes have been reviewed. The principle of temperature-sensitive SPU has been stated. Water vapor transport through dense segmented polyurethane is a collective process of diffusion and sorption and, hence, the permeability of mass molecules through dense membrane depends on both diffusion and sorption. Therefore, the study of different structural factors on water vapor transport properties are important, in order to enhance the permeability of non-porous membranes. The effects of different structural factors, viz., hard and soft segment, functional groups, hydrophilic groups, crystallites and additives on permeability have also been included in this review article.

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The Effect of Chain Length of Polyethylene Glycol on Properties of Castor Oil Based Polyurethane Elastomers

Cited by 27 publications

References 13 publications

Swelling and Diffusion Characteristics of Hydrogels Synthesized from Diepoxy-terminated Poly(ethylene glycol)s and Aliphatic Polyamines

Swelling and Diffusion Characteristics of Hydrogels Synthesized from Diepoxy-terminated Poly(ethylene glycol)s and Aliphatic Polyamines

The Effect of Plant Source on the Properties of Lignin-Based Polyurethanes

Segmented shape memory polyurethane and its water vapor transport properties

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