Investigation of the Fracture Surface of E Glass Fiber Reinforced PMMA Denture Base Resins

The interface between fibers and the acrylic resin matrix is considered to be an important factor in the reinforcement, and the microscopic surface structure may play a key role in the effectiveness of this reinforcement. Adequate adhesion of the fibers to the polymer matrix is one of the most important factors for strength. The optic microscope, although of limited resolution, is still a popular choice. The scanning electron microscope (SEM) provides measurements in 2 dimensions. The aim of the study was to examine the interfacial region of PMMA reinforced with chopped glass fibers coated with two different silans using the scanning electron microscope. E Glass fibers coupled with Silan 1 (silan + epoxy resin) and Silan 2 (silan + polyester resin) were used to reinforce denture base polymethyl metacrylate resin. Specimens were produced by two different methods in the first group, and the fibers were soaked with a mixture of polymer powder and monomer liquid. In the second group the fibers were soaked in the polymer liquid for 15 minutes and then blended with PMA polymers. All the samples were heat cured. Transverse strength of specimens was evaluated by a 3 point bending test. Fracture surfaces of the test specimens were examined with SEM to evaluate the degree of impregnation of fibers with the polymer matrix. SEM examination revealed well impregnated glass fibers with the polymer matrix. No difference was found between the test groups

The Effect of Two Different E Glass Fiber Reinforcements on Mechanical Properties of Polymethyl Metacrylate Denture Base Resins

Denture base polymers were reinforced with various types of fibers, such as glass, carbon/graphite and ultrahigh-modulus polyethylene fibers. These procedures were performed to take advantage of the good esthetic qualities of glass fibers and good bonding of glass fibers to polymers via silane coupling agents. The most common type of glass used in fiber production is the so-called E glass (electrical glass). This study investigated the effect of chopped fibers with two different silane coupling agents on the strength of denture base polymethyl metacrylate resins. E Glass fibers coupled either with Silan 1 (silan + epoxy resin) or Silan 2 (silan + polyester resin) were used to reinforce denture base polymethyl metacrylate resin. Specimens were produced by two different methods. In the first group, the fibers were wetted with a mixture of polymer powder and monomer liquid and in the second group the fibers were soaked in the polymer liquid for 15 minutes and then blended with PMA polymers. All samples were heat cured. Control group specimens were not fiber reinforced. Half of the prepared specimens were stored in distilled water at 37°C for 48 hours. The others were tested immediately. Transverse strength of all specimens was evaluated by a 3 point bending test. No significant difference was found between the wetted and immediately tested specimens (p=0.755). When all specimens were compared for transfer stength there was statistically significant difference between the wetted and unwetted specimens (p=0). When silanated and control specimens were compared the ones processed with Silan 2 (silan + polyester resin) showed the lowest transfer strenght values

Gender equality and religion:a multi-faith exploration of young adults’ narratives

This paper presents findings from research on young adults in the UK from diverse religious backgrounds. Utilizing questionnaires, interviews, and video diaries it assesses how religious young adults understood and managed the tensions in popular discourse between gender equality as an enshrined value and aspirational narrative, and religion as purportedly instituting gender inequality. We show that, despite varied understandings, and the ambivalence and tension in managing ideal and practice, participants of different religious traditions and genders were committed to gender equality. Thus, they viewed gender-unequal practices within their religious cultures as an aberration from the essence of religion. In this way, they firmly rejected the dominant discourse that religion is inherently antithetical to gender equality

The employment of migrant nannies in the UK: negotiating social class in an open market for commoditised in-home care

Migrant women are important sources of labour in the commoditised in-home childcare sector in many regions of the UK. Jobs in this sector, which include nannies as well as au pairs, babysitters, housekeepers and mothers' helps, are often low paid and low status with pay and conditions being determined by employers' circumstances and whims. This article draws on primary data and secondary sources to illustrate the ways in which employers compare migrant nannies with British nannies and other childcare workers in terms of the social class and formal education levels of different groups, with the aim of explaining why migrants are perceived as high-quality candidates for what are often low-paid, low-status jobs. I argue that employers negotiate inter-class relations in this gendered form of employment by understanding their relationship with the migrant nannies they have employed in the context of broader global inequalities—these inequalities are then reproduced and reaffirmed in private homes and across UK culture and society