Flammability of Bio-Based Rigid Polyurethane Foam as Sustainable Thermal Insulation Material

One of the biggest disadvantages of rigid polyurethane foams is its low thermal resistance, high flammability, and high smoke production when burning. Greatest advantage of this thermal insulation material is its low thermal conductivity, which at 20–25 mW/(m·K) is superior to other commercially available insulation materials. In recent years polyurethane materials from renewable resources have been widely studied. But their use on industrial scale was limited due to inconstant performance and relatively high price of raw materials. Different bio-based raw materials, such as rapeseed oil and tall oil, could provide abundant feedstock for PU foam production. Decrease of flammability of PU materials conventionally is achieved by addition of flame retardants, halogen-containing compounds, and phosphates. It can be considered that halogenated fire retardants could have several health hazards, such as volatile compound emission from materials and toxic gas release during burning process. Expandable graphite could be an answer to this flammability problem. This chapter describes development of bio-based rigid polyurethane foams and their flammability reduction using sustainable flame retardants. Different expandable graphite intumescent flame retardants provided significant flammability reduction while maintaining low thermal conductivity of insulation materials

Evolution FP7 funded project: body structure design strategies using new composite and aluminium materials and enabled technologies

Based on Pininfarina Nido EV concept, EVolution aims to reduce the vehicle weight through new materials and process technologies, focused on five demonstrators: underbody, front crossbeam, mechanical subframe, shotgun system and door. This paper refers to body structure design strategies using new composite, Al materials and enabled technologies, focusing in particular on demonstrators design and manufacturing. The new front crossbeam geometry of the front shell is adapted starting from the Nanotough design, while the rear shell is specific for EVolution. The subframe demonstrator is redesigned to fulfil mechanical requirements of the part and manufacturing feasibility either. The EVolution door concept consists of two semistructural composite skins including a structural Al frame. The underbody is conceived through an integrated approach, optimising each element for its function. The shotgun component is designed to link parts obtained with different manufacturing technologies and several aluminium alloys in one single component: the structural node demonstrator.The research leading to these results has received funding from the European Union Seventh Framework Programme (FP7/2007-2013) under grant agreement no. 314744

A Concrete and Viable Example of Multimaterial Body: The Evolution Project Main Outcomes

Funded by the EC FP7 Programme, EVolution project demonstrated that it is possible to consistently reduce the vehicle weight through the wide use of new materials and process technologies, mainly by developing a multi-material Body-in-White. This paper focuses on three of the five structural body demonstrators, the main objective of the framework, strongly hybridized with aluminum and thermoplastic composite materials, specifically developed and manufactured through innovative technologies. Directing in particular the analysis on medium production volumes (> 30,000 units/year), the industrial viability is evaluated in terms of TAKT time, lightweighting costs, weight reduction and structural performances achieved.The research leading to these results has received funding from the European Union Seventh Framework Programme (FP7/2007-2013) under grant agreement no. 314744

Reinforcement Efficiency of Cellulose Microfibers for the Tensile Stiffness and Strength of Rigid Low-Density Polyurethane Foams

Rigid low-density closed-cell polyurethane (PU) foams are widely used in both thermal insulation and structural applications. The sustainability of PU foam production can be increased by using bio-based components and fillers that ensure both enhanced mechanical properties and higher renewable material content. Such bio-based foams were produced using polyols derived from rapeseed oil and microcrystalline cellulose (MCC) fibers as filler. The effect of MCC fiber loading of up to 10 wt % on the morphology, tensile stiffness, and strength of foams has been evaluated. For estimation of the mechanical reinforcement efficiency of foams, a model allowing for the partial alignment of filler fibers in foam struts was developed and validated against test results. It is shown that although applying MCC fibers leads to modest gains in the mechanical properties of PU foams compared with cellulose nanocrystal reinforcement, it may provide a higher content of renewable material in the foams

Spieniane wodą pianki poliuretanowo-poliizocyjanurowe otrzymane z bio-polioli i modyfikowane włóknami drzewnymi

In this paper rigid polyurethane-polyisocyanurate (PUR-PIR) foam andwood fiber composites were synthesized using two types of bio-polyols. The PUR-PIR systems were modified with 3 and 6wt% of wood fibers. The influence of the content of wood fibers on the cellular structure was examined with scanning electron microscopy (SEM). Thermal and mechanical properties of the composites were characterized with thermogravimetric analysis, thermal conductivity, compressive strength, and Young modulus measurements. The influence of wood fibers on flammability of PUR-PIR foams was analyzed by oxygen index and cone calorimeter tests. For the most of foams, introduction of wood fibers did not affect the change in compressive strength. Introduction ofwood fibers increased the temperature at which thermal degradation began, as well as the temperature at which occurs 5, 25 and 50 % weight loss. The studies have shown that the oxygen index of the obtained PUR-PIR foams insignificantly decreases with increasing wood fibers content.Z użyciem dwóch rodzajów biopolioli i włókien drzewnych (w ilości 3 i 6 % mas.) otrzymano kompozyty sztywnych pianek poliuretanowo-poliizocyjanurowych (PUR-PIR). Zmiany struktury komórkowej pianek w zależności od zawartości włókien drzewnych badano za pomocą skaningowej mikroskopii elektronowej (SEM). Właściwości termiczne i mechaniczne kompozytów charakteryzowano wykonując analizę termograwimetryczną oraz wyznaczając przewodnictwo cieplne, wytrzymałość na ściskanie oraz moduł Younga. Analizując wskaźnik tlenowy i szybkość wydzielania ciepła wyznaczaną za pomocą kalorymetru stożkowego określano wpływ zawartości włókien drzewnych na palność kompozytów. Stwierdzono, że w przypadku większości materiałów dodatek włókien drzewnych nie wpływa istotnie na zmiany wytrzymałości na ściskanie, powoduje natomiast wzrost temperatury, przy której następuje 5, 25 oraz 50-proc. ubytek masy badanej próbki oraz nieznaczne zmniejszenie wartości wskaźnika tlenowego