UV Radiation Cross-linking Research Articles

A Review on various methods for the Cross-linking of Polymers

Cross-Linking the carbon atoms suffices to transform such material intoa superior material that may be resistant to temperature, pressure, corrosion, and that can be used in a variety of applications. Cross Linking is a stabilization process in polymer chemistry which leads to multidimensional extension of polymeric chain resulting in network structure. Cross-link is a bond which links one polymer chain to other. It can be ionic or covalent. Cross Linking changes a liquid polymer into ‘solid’ or ‘gel’ by restricting the ability of movement. When polymer chains are linked together by cross-links, they lose some of their ability to move as individual polymer chains. A liquid polymer (where the chains are freely flowing) can be turned into a ‘solid’ or ‘gel’ by cross-Linking the chains together. Cross Linking increases the molecular mass of a polymer. Cross-linked polymers are important because they are mechanically strong and resistant to heat, wear and attack by solvents. Cross-link property has been used to improve the insolubility, mechanical strength, stiffness, and rigidity of polymer microbeads having potential applications in solid-phase synthesis, solid-phase extraction, and biomedical fields. Hydrogels represents a class of high-water content polymers with physical or chemical crosslinks. Their physical properties are similar to soft tissues. A popular approach to attaining controlled drug delivery from polymer-based systemsinvolves the use of cross-linkers. In order to improve the properties of polymers specific toothier applications, they can be modified by either physical cross-linkers (high pressure, irradiation) or chemical cross-linkers (glutraldehyde, genipin).Therefore, synthesis of polymer with desired cross-linker (hydrophilic/hydrophobic/rigid/flexible) and concentration of cross-linker (cross-link density) is an important.Polyethylene (PE) once cross linked is advantageously employed in the fabrication of blanket insulation for electrical and telephone wires, pipes for the transport of cold and hot liquids, prostheses for the human body. In the present review, chemical cross-Linking by free-radical, condensation, UV radiation, and small-molecule cross-Linking are discussed in details.

A Review on Various Methods for the Cross-linking of Polymers

Cross-Linking the carbon atoms suffices to transform such material intoa superior material that may be resistant to temperature, pressure, corrosion, and that can be used in a variety of applications. Cross Linking is a stabilization process in polymer chemistry which leads to multidimensional extension of polymeric chain resulting in network structure. Cross-link is a bond which links one polymer chain to other. It can be ionic or covalent. Cross Linking changes a liquid polymer into ‘solid’ or ‘gel’ by restricting the ability of movement. When polymer chains are linked together by cross-links, they lose some of their ability to move as individual polymer chains. A liquid polymer (where the chains are freely flowing) can be turned into a ‘solid’ or ‘gel’ by cross-Linking the chains together. Cross Linking increases the molecular mass of a polymer. Cross-linked polymers are important because they are mechanically strong and resistant to heat, wear and attack by solvents. Cross-link property has been used to improve the insolubility, mechanical strength, stiffness, and rigidity of polymer microbeads having potential applications in solid-phase synthesis, solid-phase extraction, and biomedical fields. Hydrogels represents a class of high-water content polymers with physical or chemical crosslinks. Their physical properties are similar to soft tissues. A popular approach to attaining controlled drug delivery from polymer-based systemsinvolves the use of cross-linkers. In order to improve the properties of polymers specific toothier applications, they can be modified by either physical cross-linkers (high pressure, irradiation) or chemical cross-linkers (glutraldehyde, genipin).Therefore, synthesis of polymer with desired cross-linker (hydrophilic/hydrophobic/rigid/flexible) and concentration of cross-linker (cross-link density) is an important.Polyethylene (PE) once cross linked is advantageously employed in the fabrication of blanket insulation for electrical and telephone wires, pipes for the transport of cold and hot liquids, prostheses for the human body. In the present review, chemical cross-Linking by free-radical, condensation, UV radiation, and small-molecule cross-Linking are discussed in details.

Further discussion on the reaction behaviour of triallyl isocyanurate in the UV radiation cross-linking process of polyethylene: a theoretical study.

Further theoretical investigation on the reaction behaviour of triallyl isocyanurate (TAIC) in the UV radiation cross-linking process of polyethylene (PE) is accomplished by density functional theory for high voltage cable insulation materials. The reaction potential energy information of the 13 reaction channels at B3LYP/6–311 + G(d,p) level are identified. These have been explored that the TAIC take part in the reaction behaviour on ground state during UV radiation cross-linking process and TAIC intra-molecular isomerization reaction itself. In addition, the results show that the effect of multiplication and acceleration for the cross-linking reaction of trimethylopropane trimethacrylate (TMPTMA) would be better than that of TAIC. It has further clarified the reasons why UV radiation cross-linking reaction of PE had been initiated by benzophenone (Bp), and the TAIC or TMPTMA needed to take part. The results obtained in the present study could directly guide both the optimization of UV radiation cross-linking PE process and the development of the insulation material of high-voltage cable in real application.

Theoretical study on the grafting reaction of maleimide and its derivatives to polyethylene in the UV radiation cross-linking process

Theoretical investigation on the reactions of the maleimide and its derivatives in the UV radiation cross-linking of polyethylene is accomplished by density functional theory. The reaction potential energy surface information of 12 reaction channels is determined at the B3LYP/6-311+G(d,p) level. The highest occupied molecular orbital-lowest unoccupied molecular orbital energy gaps, ionization potentials, and electron affinities of the maleimide and its derivatives are obtained. The calculated results show that the maleimide and its derivatives can be grafted to polyethylene chain during the UV radiation process. In addition, the calculated results also show that the reaction energy barrier of 1,8-bismaleimidotriethylene glycol grafted to polyethylene is lower than that of N-phenylmaleimide, and 1,8-bismaleimidotriethylene glycol can be used as cross-linking agent. The bismaleimide grafted to polyethylene can also be used as space charge inhibitor. This survey for dual function additive is expected to provide reliable information for the development of UV radiation cross-linking polyethylene process and high-voltage insulation cables exceed 500 kV in real application.

Theoretical Study on the Grafting Reaction of Maleimide to Polyethylene in the UV Radiation Cross-Linking Process.

Theoretical investigation of the reaction of graft maleimide to polyethylene in the UV radiation cross-linking process is accomplished at the B3LYP/6-311+G(d,p) level for high-voltage cable insulation materials. The reaction potential energy surface of the nine reaction channels is identified. The results show that the N,N′-ethylenedimaleimide can connect two 4-methylheptane molecules and act as the cross-linking agent. The calculated reaction potential barrier of forming 4-methylheptane radical by maleimide is higher than that of maleic anhydride. The study is expected to provide a basis for optimizing the UV radiation cross-linking polyethylene process and development more than 500 kV high-voltage cable insulation materials in practical applications.

Theoretical study on the reaction of maleic anhydride in the UV radiation cross-linking process of polyethylene

Theoretical investigation on the reaction of maleic anhydride (MAH) in the UV radiation cross-linking process of polyethylene as high voltage cable insulation materials is accomplished at B3LYP/6-311 + G(d,p) level. The reaction potential energy information of 10 reaction channels is identified. The results show that the UV radiation cross-linking reaction of polyethylene is initiated by benzophenone, and the multi-functional crosslinker triallyl isocyanurate (TAIC) is needed to take part in the cross-linking process. The behavior of grafting the polar group MAH onto the polyethylene is explored in detail at atomic and molecular levels during UV radiation cross-linking process. The investigation is expected to provide reliable information for optimizing polyethylene UV radiation cross-linking process and for the development of the insulation material of high-voltage cable exceed 500 kV in real applications.

Theoretical study on the reaction of triallyl isocyanurate in the UV radiation cross-linking of polyethylene

Herein, a theoretical investigation on the reaction potential energy surface information of triallyl isocyanurate (TAIC) in the UV radiation cross-linking process of polyethylene is conducted at the B3LYP/6-311+G(d,p) level for the production of high voltage cable insulation materials.

Theoretical study on the reaction mechanism in the UV radiation cross-linking process of polyethylene

The grafting of the valerophenone as voltage stabilizer to the polyethylene molecule chain is possible in the UV radiation cross linking process. This is useful for preparing insulation cables of high voltage up to 500 kV in real application.

Surface modification of electrospun poly(methyl methacrylate) (PMMA) nanofibers for the development of in vitro respiratory epithelium model

Scaffold design is an important aspect of in vitro model development. In this study, nanoscaffold surface modification, namely UV radiation and genipin cross-linking to immobilize collagen on the surface of electrospun poly (methyl methacrylate) (PMMA) nanofiber sheet was investigated. Samples were divided into four groups; PMMA nanofibers (PMMA), collagen-coated PMMA nanofibers (PMMACOL), genipin cross-linked collagen-coated PMMA nanofibers (PMMAGEN), and UV-irradiated collagen-coated PMMA nanofibers (PMMAUV). 6 h of UV radiation significantly reduced the hydrophobicity of PMMA nanofibers from (131.88° ± 1.33°) to (110.04° ± 0.27°) (p < 0.05). The amount of collagen immobilized was significantly higher in PMMAGEN group (239.36 ± 16.63 μg collagen/mg nanofibers) (p < 0.05) compared to the other groups. RECs on all scaffold expressed epithelial cell-specific markers (CK18 and CK14), mucin-producing cell marker (MUC5Ac) and were actively proliferating, based on the positive expression of Ki67. Total number of attached cells was significantly the highest in PMMAUV group on day 9 (6.44 × 104 ± 2.77 × 104 cells/cm2) and it has the highest proliferation rate from day 4 to 9 (0.005 ± 0.003 h−1) compared to the other groups. Even though PMMAGEN group showed the highest collagen adsorption, in terms of cells attachment and proliferation, PMMAUV group showed a better outcome compared to the other groups. Thus, PMMAUV scaffold is more suitable to be used in the construction of in vitro respiratory epithelial model.