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- Green nanocomposites from rosin-limonene copolymer and algerian clayPublication . Derdar, Hodhaifa; Mitchell, Geoffrey; Mahendra, Vidhura; Benachour, Mohamed; Haoue, Sara; Cherifi, Zakaria; Bachari, Khaldoun; Harrane, Amine; Meghabar, RachidGreen nanocomposites from rosin-limonene (Ros-Lim) copolymers based on Algerian organophilic-clay named Maghnite-CTA+ (Mag-CTA+) were prepared by in-situ polymerization using di erent amounts (1, 5 and 10% by weight) of Mag-CTA+ and azobisisobutyronitrile as a catalyst. The Mag-CTA+ is an organophilic montmorillonite silicate clay prepared through a direct exchange process; the clay was modified by ultrasonic-assisted method using cetyltrimethylammonuim bromide in which it used as green nano-filler.The preparation method of nanocomposites was studied in order to determine and improve structural, morphological, mechanical and thermal properties ofsin.The structure and morphology of the obtained nanocomposites(Ros-Lim/Mag-CTA+) were determined using Fourier transform infrared spectroscopy, X-ray di raction, scanning electronic microscopy and transmission electronic microscopy. The analyses confirmed the chemical modification of clay layers and the intercalation of rosin-limonene copolymer within the organophilic-clay sheets. An exfoliated structure was obtained for the lower amount of clay (1% wt of Mag-CTA+), while intercalated structures were detected for high amounts of clay (5 and 10% wt of Mag-CTA+). The thermal properties of the nanocomposites were studied by thermogravimetric analysis (TGA) and show a significant improvement inthe thermal stability of the obtained nanocomposites compared to the purerosin-limonene copolymer (a degradation temperature up to 280ºC).
- Regional Innovation Ecosystems: Tuning the Regional Engine’s Helix Through Smart SpecializationPublication . Lopes, João; Ferreira, João J.; Oliveira, Márcio; Farinha, Luís; Oliveira, JoséThe present research aims to contribute for the analysis of the theoretical evolution of the triple helix, quadruple helix, quintuple helix and multiple helix concepts, embracing the dynamic interaction of different stakeholders in the context of regional innovation systems. Following a preliminary literature review on the subject, it was possible to develop a systematic literature review with a bibliometric analysis of research that addressed the evolution of the triple helix until the multiple helix, into the regional innovation systems perspective. Extensive research was conducted using the Web of Science database between 1990-2018, covering a total of 378 articles, generators of 9991 citations. Four clusters were found in the literature for this field of research: R&D Collaborations and Innovation; Entrepreneurial Activity in Entrepreneurial University; Triple Helix Dynamics, and Quadruple Helix in Regional Innovation Systems. New theoretical perspectives based on bibliometric analysis and new research paths have been identified, aiming to better understand the regional interaction of stakeholders for innovation and entrepreneurship.