UV and Gamma Irradiation Effects on Surface Properties of Polyurethane Derivate from Castor Oil

Azevedo, Elaine Cristina; Nascimento, Eduardo Mauro do; Chierice, Gilberto Orivaldo; Neto, Salvador Claro; Lepienski, Carlos Maurício

doi:10.4322/polimeros.2013.087

Cited by 22 publications

(11 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In another study on the influence of electron-beam irradiation in air on the chemical and the structural properties of medical-grade polyurethane, the results show homogeneous oxidative degradation followed by a decrease in molecular mass and an increase in polydispersity [13]. The chain scission is common by the irradiation UV and gamma irradiation in air of polyurethane [14]. In this paper we irradiated polyurethane film in isolated of air under vacuum conditions.…”

Section: Introductionmentioning

confidence: 97%

“…The intensity of this peak increased with radiation doses being increased. Also X-ray diffraction curves indicate a decrease in d-spacing (Å) corresponding to a lower distance between aromatic rings from MDI [14] is controlled by the gamma irradiation doses. The change of crystallinity can be explained by the degree of crosslinking of the PU samples.…”

Section: Effect Of Irradiation Doses On the Crystallinity Of Crosslinmentioning

confidence: 99%

See 1 more Smart Citation

Radiation Crosslinking of Polyurethanes: Characterization by FTIR, TGA, SEM, XRD, and Raman Spectroscopy

Ghobashy

Abdeen

2016

Journal of Polymers

View full text Add to dashboard Cite

Gamma radiation can be used for enhancing the physical properties of polyurethane (PU). Radiation was used to crosslink a polyurethane at room temperature; four samples of the PU solid film are irradiated at variable four radiation doses 0, 50, 100, and 150 kGy under vacuum conditions. Crosslinking radiation is more common than oxidative degradation and crosslinking is believed to be more efficient in the soft segment of PU. The structure of the PUs is performed by Fourier transform infrared (FTIR-ATR), Thermogravimetric Analysis (TGA-DTG), and X-ray Diffraction (XRD) which have been used to investigate the effect of gamma radiation on the polyurethane (PU). The results showed that the radiation crosslinking of polyurethanes improved the thermal stability and the crystallinity. The microstructure modifications of polyurethane samples have also been studied as a function of the dose using the scanning electron microscope (SEM). The effects of gamma irradiation on the color changes of polyurethane were observed. The irradiated PUs have conjugated structure and are capable of emitting purple fluorescence.

show abstract

Section: Introductionmentioning

confidence: 97%

Section: Effect Of Irradiation Doses On the Crystallinity Of Crosslinmentioning

confidence: 99%

Radiation Crosslinking of Polyurethanes: Characterization by FTIR, TGA, SEM, XRD, and Raman Spectroscopy

Ghobashy

Abdeen

2016

Journal of Polymers

View full text Add to dashboard Cite

show abstract

“…Table 1 shows the flexural properties of polyurethane derived from castor oil before and after the gamma irradiation with dose of 25 kGy. A slight increase on flexural stress and flexural elastic modulus after irradiation is noticed, which, according to Azevedo et al [8,30] , can be attributed to the formation of crosslink bonds in the polymeric chains caused by the gamma radiation incidence. Figure 1 shows the obtained TGA curves of the dispersed fibers composite without irradiation.…”

Section: Methodsmentioning

confidence: 80%

“…The effects of gamma radiation in polyurethane derived from castor oil adhesive specimens were studied by Azevedo et al [8] , and they concluded that there were no significant alterations of the mechanical properties when materials were irradiated with doses up to 100 kGy, since the main effect of radiation in this polymer is the formation of cross-linked bonds within polymeric chains.…”

Section: Introductionmentioning

confidence: 99%

Gamma radiation effect on sisal / polyurethane composites without coupling agents

et al. 2017

View full text Add to dashboard Cite

Natural fibers and polyurethane based composites may present chemical bonding between the components of the polymer and the lignin of the fiber. The incidence of radiation can cause degradation of the polymeric material and alter its mechanical properties. The objective of this study was to obtain and characterize cold pressed composites from polyurethane derived from castor oil and sisal fibers, without coupling agents, through thermogravimetric and mechanical tests, before and after the incidence of 25 kGy dose of gamma radiation. Woven composites that were not irradiated had maximum values of 4.40 GPa for flexural elastic modulus on three point flexural test and dispersed fiber composite that were not irradiated had maximum values of 2.25 GPa. These materials are adequate for use in non-structural applications in radiotherapy and radiodiagnostic rooms.

show abstract

“…Polyurethane derived from castor oil is a biodegradable polymer produced from renewable sources, and it is harmless to human health and to the environment, since no volatile organic compounds are liberated in its synthesis [6,14,15] . During polyurethane polymerization in the presence of vegetable fibers, crosslinks may result from the reaction of active hydrogens from hydroxyl or carboxyl groups from lignin and PU free isocyanate.…”

Section: Introductionmentioning

confidence: 99%

The influence of fiber size on the behavior of the araucaria pine nut shell/PU composite

et al. 2019

View full text Add to dashboard Cite

ObstractThe use of araucaria pine nut shell in polymer composites may increase the pine nut value and help protec araucaria (Araucaria angustifolia) itself, which is an endangered species. The aim of this work is to study the influence of the size of pine nut shell fiber on the mechanical properties of composites made of this shell and polyurethane derived from castor oil. Composites with different polyurethane contents were manufactured with dried untreated pine nut shell sieved through 30 and 50 mesh sieves (0.6 and 0.3 mm, respectively). Composites were shaped by mechanical mixing of the components followed by hot pressing. Properties such as density, water absorption, and flexural strength were measured. Specimens were also characterized by SEM, FTIR, and TGA. The flexural strength of PU/0.3mm pine nut shell composites with 30% PU (wt%) was 57.7 MPa, and their water absorption was 7.37% after 24 hours of immersion.

show abstract

UV and Gamma Irradiation Effects on Surface Properties of Polyurethane Derivate from Castor Oil

Cited by 22 publications

References 0 publications

Radiation Crosslinking of Polyurethanes: Characterization by FTIR, TGA, SEM, XRD, and Raman Spectroscopy

Radiation Crosslinking of Polyurethanes: Characterization by FTIR, TGA, SEM, XRD, and Raman Spectroscopy

Gamma radiation effect on sisal / polyurethane composites without coupling agents

The influence of fiber size on the behavior of the araucaria pine nut shell/PU composite

Contact Info

Product

Resources

About