Crosslinks thermoreversible

Xue, W. Champ, S. Huglin, M.B. Network and swelhng parameters of chemically crosslinked thermoreversible hydrogels. Polymer 2001, 42, 3665-3669. 

Aroylopectin Solution of sufficiently high concentration formed physicaliy crosslinked thermoreversible gels upon cooling to below room temperature. Durrani and Donald, 1995... 

Inoue K, Yamashiro M, Iji M (2009) Recyclable shape-memory polymer poly(lactic acid) crosslinked by a thermoreversible Diels-Alder reaction. J Appl Polym Sci 112 876-885... 

Thermoreversible Crosslinking of Silicones Using Acceptor-Donor Interactions... 

The hard segment aggregates act as physical crosslinks and-this thermoreversible three - dimensional network formation accounts for the properties of these thermoplastic elastomers. 

Te Nijenhuis K (2007) On the nature of crosslinks in thermoreversible gels. Polym Bull 58 27-42... 

In chemical gels the network connection (crosslink) is usually a covalent bond, which leads to a thermally irreversible gel. When the crosslinking is purely physical in nature, a physical gel is formed which is thermally reversible. There have been at least two excellent works published in the last few years. Reversible Polymeric Gels and Related Systems by Russo [2] and Thermoreversible Gelation of Polymers and... 

The results above are only valid for tetrafunctional crosslinking of monodisperse polymer. However, in many thermoreversible systems the crosslinks have functionalities that are much larger than four. Moreover, the polymers used are not monodisperse in general. In order to be able to calculate network parameters the present author [39—44] extended the Flory-Stockmayer model for polydisperse polymer which is crosslinked with f-functional crosslinks. It was possible to calculate network parameters for polymers of various molecular weight distributions (monodisperse polymer with D s M, /r3 = 1, a Schulz-Flory distribution with D = 1.5, a Flory distribution with D = 2, a cumulative... 

Examples of physical crosslinks are microcrystalline aggregates, entangled chains, ionic interactions between charged atoms or groups of atoms, and hydrogen bonds. Physical gels are also reversible because the physical crosslinks can be created and removed by appropriate physical stimuli (e.g., pH, contact with a nonsolvent, etc.), and, typically, temperature. For this reason, they are often named thermoreversible. ... 

Gels with crystal fragments as crosslinks are, as a rule, thermoreversible due to the liquidus curve being intersected while the configurative point moves along the temperature axis. 

In contrast to crosslinked gels, thermoreversible gels must po.s.sess the elastic modulus which is an extremal function of temperature far from the melting temperature of crystallites, Equation 50 with u = const holds good, while near this temperature, the reduction... 

Specific types of polymer micropatterns were made of crosslinked and uncrosslinked poly(methacrylic acid) and poly(N-isopropyl acrylamide) or polyNI-PAM. Also, the spacer material between the Si wafers was adjusted to hundreds of micrometers, allowing for a single-exposure high aspect ratio microlithography of theses polymers. Also, since these polymers under go LCST behavior during polymerization conditions, they are suitable as thermoreversible gels during application. 

These multicomponent PP blends have been developed during the last ten years. For example, they comprise (1) either an acidified-PP, its mixture with PP, or a mixture of PP with carboxylic acid-modified EPR (2) poly(methylmethacrylate-co-styrene-co-maleic anhydride) and (3) either ethylene-methylmethacrylate-glycidylmethacrylate, or ethylene-vinylacetate-glycidylmethacrylate. The compatibilization is obtained by chemical reactions between the acid and epoxy groups, as well as by forming ionic clusters capable of forming thermoreversible crosslinks. The blends were used to mold car bumpers and fenders. The products showed good stiffness and low-temperature impact resistance [8]. 

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