Nanocomposite materials: from lab-scale experiments to prototypes

Abstract

A porous PMMA material has been reinforced by clay particles, and properties of the resulting material were evaluated. The clay has been intercalated in a first step by melt-extrusion with a suitable block copolymer. A radical polymerisation reaction after swelling of the intercalated clay with monomer leads in a subsequent step to a nanocomposite material with improved mechanical properties. The optimum load of modified clay was determined to be about 3 to 4 wt.-%. A separation of the reinforcing mineral into single sheets and a subsequent homogeneous incorporation of these sheets into the polymer matrix material increased different mechanical properties by approximately 60%. The lifetime of porous polymer moulds used for pressure casting of sanitary ware has been analysed, modelled and increased. The mechanical behaviour of the existing porous PMMA mould material was analysed using mechanical tests to assess the lifetime under cyclic loading. The relevant stress levels were obtained through in situ strain gauge measurements on a polymer mould for the production of a washing basin. These results were confirmed by means of finite element stress analyses. The lifetime of the washing basin mould under the relevant production conditions was predicted from these data and found to be in good agreement with practical experience. A method to improve the limited lifetime under higher pressures was developed by applying nanodispersed clay as reinforcement. The improved material shows an increase in lifetime under cycling loading by about 1000% in mechanical tests. This improvement is confirmed for a pressure casting mould made of the improved material when used in the actual production process.

Polymethyl methacrylate based open-cell porous plastics for high-pressure ceramic casting

“…The reduction of the mechanical properties is related to the porosity increase from 34 to 47% for the given concentration range, respectively. Also, the densities of the tested materials changes from 0.803 to 0.762 g/cm 3 for the same concentration range. The material with a high density exhibited a short deformation plateau (in region II) in the stress-strain graphs.…”

“…To our knowledge, there is very limited work reported in the literature about the subject. In some recent studies, it was attempted to improve the mechanical performance of the porous moulds by addition of reinforcing components such as clay particles into the plastic structure [2][3][4].…”

Porous nanocomposites prepared from layered clay and PMMA [poly(methyl methacrylate)]

“…Therefore, it has been commonly employed in automotive, transportation, construction, biomaterials, and other applications. In addition, these materials have been recently used as molding material in the fabrication of ceramic whiteware and sanitaryware articles with slip casting technique that has been traditionally performed using plaster molds [1,2]. Due to the long casting periods (1-2 h), long drying time and limited service life of the plaster of Paris, the trend in the ceramic industry is the utilization of the high pressure casting process that provides automation.…”

“…Due to the long casting periods (1-2 h), long drying time and limited service life of the plaster of Paris, the trend in the ceramic industry is the utilization of the high pressure casting process that provides automation. In this technique, a porous mold material that allows the drainage of water from the slip under high pressures of typically 13-15 bars is needed [1,2]. The materials with an open cell structure need to provide high water permeability, high mechanical strength and fatigue performance.…”

“…In only a recent study, Dortmans et al [12] prepared porous nanocomposites by incorporation of the clay sheets into the PMMA porous matrix during polymerisation using a PEO-PMMA block copolymer. A significant improvement in mechanical properties and in lifetime was obtained.…”