UV-light induced crosslinking reaction of cinnamate natural rubbers: Effect of the spacer length, counter-ion nature, and content

ABSTRACT:Crosslinked electrospun polybutadiene (BR) fibers were made using electrospinning and UV curing methods. The crosslinked BR fibers were obtained by irradiating UV light on the electrospun BR fibers containing a photoinitiator and a crosslinker. Although uncrosslinked electrospun BR fibers did not retain the fiber morphology at room temperature due to a cold flow resulting from the very low glass transition temperature (T g ) of BR (below Ϫ80°C), the crosslinked electrospun BR fibers retained the fiber morphology. The crosslink density increased with increase of the content of crosslinking agent. The crosslinked BR fibers had higher T g than the raw BR. Tensile strength, modulus, and elongation at break of the electrospun BR fiber mats increased with increase of the crosslinker content.

Section: Resultsmentioning

confidence: 99%

“…Based on the requirement mentioned earlier, we selected a UV curing system,17–21 which has well‐defined technology in a variety of industrial applications. Highly crosslinked polymers can be generated within seconds at ambient temperature with the UV cure system.…”

Section: Introductionmentioning

confidence: 99%

Fabrication and characterization of electrospun polybutadiene fibers crosslinked by UV irradiation

Choi

Hong

Seo

et al. 2006

“…As part of our continuing interest in preparing PLA‐based composite materials showing high performance, the present work also indicates the use of maleinized polybutadiene rubber as a coupling agent in FPF‐reinforced composites. In the recent years, graft copolymers of maleic anhydride (MA) with synthetic and natural polymers have been studied, and the graft copolymerization of maleic hydride onto the natural rubber molecules was carried out in molten11 or solution states 12. Hristov et al13 investigated the effects of poly(butadiene styrene) rubber and maleated polypropylene used as impact modifier and compatibilizer, respectively, in the case of polypropylene (PP)/wood fiber composites.…”

Section: Introductionmentioning

confidence: 99%

Effect of fiber surface treatment of poultry feather fibers on the properties of their polymer matrix composites

Huda

Schmidt²,

Misra

et al. 2012

This study develops the enabling technology needed to transform the fibers of poultry feather (FPF), a waste product left over after processing poultry in the food processing industry, as reinforcement filler material for manufacturing composite materials. We successfully fabricated composite materials from biopolymers (polylactide, PLA) and FPF that were produced by the extruder system. FPF-reinforced polypropylene (PP) composites were also compounded and molded and compared to PLA/FPF composite. The composites were evaluated via thermal and mechanical analysis. To enhance the adhesion between the polymer matrix and the FPF, the FPF have been treated with sodium hydroxide, 10% maleinized polybutadiene rubber, and a silane-coupling agent. X-ray photoelectron spectroscopy was used to analyze the influence of modifications on the properties of fibers and found that the coupling agent was localized at the surface of the fibers. Thermal behavior of pretreated fibers was also studied by thermogravimetric analysis. All treatments clearly enhanced thermal performance of fibers. This enhancement of fiber properties, along with an improvement in fiber/matrix adhesion, led to improvement in the mechanical properties of the composite materials. It was found that the surfacetreated fiber-reinforced materials offered superior mechanical properties compared to untreated fiber-reinforced composite materials. Moreover, morphological studies by the scanning electron microscopy demonstrated that better adhesion between the fiber and the matrix was achieved especially for the surface-treated fiber-reinforced composite materials.

“…As shown in Figure 3 and 4, the extent of the photocure reaction conversion increased with UV intensity in these photoreactive polymers. Although a distinct feature of photoinitiated polymerization is that the initiation rate can be varied in a large range by a change in the light intensity because of polymerization quantum yield,13 the rate constant in cinnamate photoreactions such as with these photoreactive polymers without photoinitiators is linearly dependent on the intensity of incident light 14…”

Section: Resultsmentioning

confidence: 99%

Photocure properties of high‐heat‐resistant photoreactive polymers with cinnamate groups

Kim

2007

New high-heat-resistant photoreactive polymers with cinnamate groups were synthesized by the reaction of cinnamic acid (CA) and epoxy resins. Their photocure properties were investigated with Fourier transform infrared spectroscopy, UV-visible spectroscopy, and thermogravimetric analysis (TGA). Their photocure reaction rates and the extent of reaction conversion increased with the intensity of UV irradiation. To investigate their photocure reaction kinetics, their reaction conversion rates were plotted against reaction conversion so that their photocure reactions could be analyzed in terms of an nth-order kinetics reaction equation. The YX4000H-CA photoreactive polymer with a biphenyl moiety, which was expected to have strong molecular interactions, showed a lower reaction conversion rate and reaction constant, and the highest reaction conversion rate and reaction constant was observed in XP2030-CA with an optimum cure reaction space and a reduction of molecular interactions compared with the other photoreactive polymers. Thermal stability was studied by observation of the changes in the transmittance of the photocured polymer films upon heating and by measurement of the weight loss with temperature with TGA. These photoreactive polymers showed good thermal properties, with almost no transmittance change in the visible range even after they were heated at 2508C for 1 h, and they exhibited little weight loss up to about 2508C.