The influence of processing parameters on interphase morphology in polymer composites based on phase-separating thermoplast/epoxy blends

In this study the occurrence of interfacial phase separation in fibre-reinforced composites has been investigated using phase-separating polystyrene/epoxy and polystyrene/poly(phenylene ether)/epoxy blends as a matrix system. The influence of surface tension and polarity of the different constituents, viscosity of the blend and reaction rate of the epoxy resin, on the resulting morphology of the interfacial epoxy phase formed during cure, have been studied. Morphological studies on short-fibre-reinforced composites showed that increasing fibre surface tension results in a decreasing contact angle of the interfacial epoxy phase on the fibre. Lowering viscosity results in an increased wetting of the fibres by the epoxy phase. In the temperature range studied, the viscosity rather than the epoxy reaction rate determines the morphology of the epoxy interphase

Blends of poly(ethylene terephthalate) and epoxy as matrix material for continuous fibre reinforced composites

The morphology and mechanical properties of poly(ethylene terephthalate) (PET)-epoxy blends and the application of these blends in continuous glass fibre reinforced composites have been investigated. Epoxy resin was applied as a reactive solvent for PET to obtain homogeneous solutions with a substantially decreased melt viscosity. The epoxy resin in these solutions was cured using an amine hardener according to two different schedules. In the first, high temperature curing at 260°C preceded low temperature crystallisation of the PET at 180°C. In the second, the PET was allowed to crystallise prior to low temperature curing at 180°C. After cure, all blends revealed a phase separated morphology of dispersed epoxy in a continuous PET matrix. The flexural strength and failure strain of all cured blends showed an increase with increasing epoxy content, whereas the high temperature cured blends exhibited overall lower flexural properties than those cured at the lower temperature. Microstructural analysis and flexural properties of continuous glass fibre reinforced PET-epoxy laminates showed that the composites obtained had a low void content. These PET-epoxy laminates had increased inplane shear strength in comparison with unmodified PET based laminates, indicating considerably increased fibre-matrix adhesion

Lower cortisol levels and attenuated cortisol reactivity to daily-life stressors in adults with 22q11.2 deletion syndrome

Background: 22q11.2 deletion syndrome (22q11DS) is a genetic disorder associated with neurodevelopmental, anxiety and mood disorders, as well as an increased risk for developing psychosis. Cortisol levels and stress reactivity reflect hypothalamic-pituitary-adrenal (HPA)-axis activity, and are believed to be altered in individuals that often experience daily-life stress, depression, and psychotic symptoms. However, it is unknown whether individuals with 22q11DS display an altered stress reactivity. Methods: We included 27 adults with 22q11DS (mean age: 34.1 years, 67% female) and 24 age and sex-matched healthy controls (HC; mean age: 39.9 years, 71% female) into an experience sampling study. Throughout 6 consecutive days, we measured participants’ subjective stress related to current activity and at the same time collected salivary cortisol samples. Multilevel regression models were used to analyze cortisol reactivity to activity-related stress. Results: Diurnal cortisol levels were significantly lower in the 22q11DS group compared to HCs (B=-1.03, p < 0.001). 22q11DS adults displayed significantly attenuated cortisol reactivity to activity-related stress compared to HCs (B = −0.04, p = 0.026). Post-hoc exploratory analysis revealed that these results were independent from 22q11DS psychiatric diagnosis or medication use. Conclusion: These results indicate that adults with 22q11DS have lower cortisol levels and attenuated cortisol response to daily stress, possibly resulting from an increased sensitization of the HPA-axis. This suggests that alterations in HPA-axis functioning, previously reported in several psychiatric disorders including post-traumatic stress disorder (PTSD), psychotic disorder, and mood disorder, also appear to be present in adults with 22q11DS

Feminist policymaking in turbulent times: critical perspectives

Feminist Policymaking in Turbulent Times offers a unique and timely reflection of the critical debates around the institutionalisation of feminist and gender-focused ideas and norms into policy. Many states and non-governmental organisations are increasingly invested in ‘feminist policymaking’ at the domestic and international levels. Yet, this liberal (feminist) agenda is also vastly disputed by critical, intersectional and decolonial voices on the one hand, and by anti-gender movements around the world on the other. Indeed, while opposition to ‘gender ideology’ is mounting from reactionary, religious and secular forces, feminist policymaking is also being challenged in important ways from within. Thus, this book situates feminist policymaking in a challenging and 'turbulent', global context. This book explores feminist policymaking in multiple areas of policy, examining various gender-focused programmes that states and international organisations have undertaken in the last decade, offering critical interventions and rethinking the relationship between feminism and policy. The book not only reflects on the advances of feminist policymaking globally, but also critically assesses the intersectional challenges embedded within it and lying ahead. It moves the field forward by creating opportunities, based on lived experiences, for re-imagining the transformative potential of the nexus between feminist and policymaking. Interdisciplinary in scope and bringing to the fore the voices of both academics and practitioners, the book is the product of an international collaboration, forging links and dialogue that are increasingly necessary to question some of the exclusionary, militaristic, and hierarchical assumptions of policymaking which is labelled as feminist. Feminist Policymaking in Turbulent Times will be of interest to all scholars, students and practitioners interested in the role of gender in policymaking and concerned with contestations around gender-focused projects