Low Styrene Emission Research Articles

COMPARISON BETWEEN NORSODYNE AND TRADITIONAL PLASTINATION MATERIALS

Background: Norsodyne is a new material which initially is semiliquid, but under the action of a hardener is solid and transparent, and stays in this state interminable. Therefore, it is comparable to the BiodurP35 and BiodurP40 products that are used to make brain sheets. According to the manufacturers, Norsodyne H 13212 TAE that we use, is unsaturated polyester resin in styrene with low styrene emission for general purpose. We take for granted that in solid form. Comparison: Biodur P35 and P40 (BiodurTM, Heidelberg, Germany) are Polyester Co-polymers. The dehydrated brain plates are impregnated with this material and then solidified under UV light. The process lasts for 2 to 8 weeks. The final preparations are transparent, solid and safe for human health. Inclusion of the anatomical material in Norsodyne takes just a few minutes, and curing takes 15 to 30 minutes. The final preparations are transparent and solid too. We have no final data that Norsodyne is safe for human health. Conclusion: Due to the rapid production and high quality of the obtained with Norsodyne anatomical preparations, they can be used for anatomy training at medical universities, but after establishment of their safety.

CHARACTERISTICS OF NORSODYNE AS PLASTINATION AGENT

Background: Norsodyne is a new material for conservation and durable preservation of biological objects. The form we use is H 13212 TAE (Polynt Composites USA, Inc., Bergamo, Italy). This is an unsaturated polyester resin in styrene that is of low styrene emission. Features: resin has a specific weight 1.10 g/cm2 at 20°C. Using test method MT-CUT23V the manufacturer has established that Brookfield viscosity at 23°C is 450-650 mPa.s. The jelly starts in 14-18 minutes and reaches its peak in 27-37 minutes at 23°C too. Acording to the test results of ISO 527 (2012) tensile strength of Norsodyne is 57 MPa and flexural strength is 98 MPa (ISO 178 (2011). Conclusion: This characteristic of Norsodyne indicates that the material can be used for the preservation and long-term storage of anatomical preparations for the needs of anatomy training. However, the Norsodyne needs special storage conditions. The material should be stored in a dark place. According to the manufacturer shelf life at 23°C in the dark is six months then spontaneous rubbing begins. The manufacturer's recommendations are: Store in the shade, out of direct sunlight. Keep storage temperature below 25°C. Unseal container just before use. Shelflife will be reduced reaching higher temperature.

Experimental evaluation of static and dynamic properties of low styrene emission vinylester laminates reinforced by natural fibres

The aim of this experimental investigation is to perform a thorough analysis in terms of mechanical properties of thermoset composites built with an eco-friendly resin and reinforced by natural fibres. Flax and basalt were the reinforcements selected, being applied both in single and hybrid layouts with a low-styrene emission (LSE) vinylester matrix, and glass synthetic fibre composites were also studied for comparison purposes. Tensile, flexural and low-velocity impact tests were carried out according to their respective ASTM standards, showing that basalt and flax laminates are respectively the strongest and the weakest materials analysed, where the hybrid composition offers similar tensile and flexural moduli to glass, being 30% stronger in tension and 10% in bending. Impact tests performed at a same shock energy of 30.6 J perforated glass fiber specimens, while small indentations were noticed in naturally reinforced coupons characterized by fiber tensile breakage and matrix compressive failure regions.

End-Cap Modified Unsaturated Polyesters With Low Styrene Emission

A benzyl end-cap-unsaturated polyester resin (BP-UPR) with low styrene emission was synthesized. The structure of BP-UPR was characterized by Fourier transform infrared (FT-IR) spectroscopy. According to gel permeation chromatography (GPC) measurement, the BP-UPR has a relative low molecular weight (Mn=1754) and narrow polydispersity of 1.68. The styrene content of BP-UPR is only 25.1%, 8.3% lower than that of a commercial unsaturated polyester resin (C-UPR) with similar viscosity. The styrene emission of BP-UPR and C-UPR was compared by Luong–Walewski method. At the gel point (17 minutes), the styrene emission of BP-UPR is only 38.9g/m2, 15.9% lower than that of C-UPR. After curing for 2 hours, the total styrene emission of BP-UPR is only 62.5 g/m2, which is 48.0% lower than that of C-UPR.

Seawater ageing of low styrene emission resins for marine composites: Mechanical behaviour and nano-indentation studies

Polyester resins are widely employed for pleasure boat construction. In order to satisfy new environmental legislation on styrene emissions resin suppliers have proposed modified formulations, but these show lower failure strains under tensile loading. This paper examines the influence of wet ageing on mechanical properties of low styrene polyester, together with standard polyester and vinyl ester resins, and their glass reinforced composites. Results are presented from accelerated ageing in natural sea water for nine months, at temperatures of 20, 40 and 60 °C. Nano-indentation was used to study local changes in the resin after ageing. The diffusion kinetics of the low styrene emission resins and their composites are similar to those for standard polyester resins. The low styrene resins appear to lose strength more slowly than the standard resins but after nine months in seawater at 40 °C similar property losses are noted.

Damage Resistance of Composites Based on Glass Fibre Reinforced Low Styrene Emission Resins for Marine Applications

Composites based on glass fiber reinforced low styrene emission polyester resins have been widely used over the last 10 years, in order to meet increasingly strict safety regulations, particularly in the pleasure boat industry. Previous studies of their mechanical properties suggested that although these resins are generally more brittle than traditional orthophthalic polyester resins this did not adversely affect the properties commonly used for quality control (short beam shear and tensile failure strength of mat reinforced composites). In the present paper results from a more detailed study of damage behaviour are presented. Tests include fracture toughness (K Ic ) tests on resins, fibre/matrix interface energy, detection of composite damage initiation in tension by acoustic emission, composite delamnation (G Ic and G IIc ), and low energy impact. Overall the results indicate that the low failure strain of low styrene emission resins results in significantly lower composite damage resistance.

Mechanical Properties of Composites Based on Low Styrene Emission Polyester Resins for Marine Applications

Glass fibre reinforced polyester composites are used extensively for hulls and decks of pleasure boats. Boat-builders must optimise manufacturing technology, not only with respect to mechanical properties but also limiting volatile organic compounds (VOC) emissions. One way to achieve this is through modified polyester resin formulations such as low styrene content, low styrene emission or combinations of these. The resin matrix selection procedure is based on design specification (mechanical behaviour) but also manufacturing requirements and cost considerations. For this application post-cure is rarely used so it is important to optimise curing conditions. In this study the influence of the curing cycle on mechanical properties was examined first for two polyester resins. Then for one cycle (16 h at 40°C) the properties of eight resins have been determined. Significant differences in failure strain are observed, from 0.9% to 3.3%. The resins with improved VOC performance are the most brittle. The transverse tensile behaviour of these resins in composites with unidirectional glass fibre reinforcement and the limit of linearity for composites with glass mat both depend on these failure strains. These results are discussed in terms of admissible composite strains for boat design.

Influence of mechanical stresses on the hydrolytic aging of standard and low styrene unsaturated polyester composites

AbstractStandard and low styrene emission glass fiber‐reinforced unsaturated polyester (FRP) composites were aged by immersion under flexural and tension loads, to evaluate modifications to the mechanical properties as a function of exposure time under stress. The application of a mechanical load does not modify either the quantity of the absorbed water or the diffusion coefficients significantly. For an applied stress of less than 10% of the fiber strength, the influence on aging is small, but for larger applied stresses, the rate of reduction in the mechanical properties is accelerated and, in some cases, premature rupture is observed. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 2185–2195, 2002

Microscopy of the morphology in low styrene emission glass fiber/unsaturated polyester laminates

Low styrene emission (LSE) unsaturated polyester resins are of interest in the context of increasing environmental concerns in the society. LSE resins have been developed to decrease styrene emission during the processing of composites based on unsaturated polyesters. In this article we applied a microscopy methodology to study morphology effects in laminates based on LSE polyesters. The study connects to the longer term objective to improve the understanding of how additives reduce styrene emission without imparting delamination resistance in composite laminates based on LSE polyesters. The major morphology differences between laminates made from different polyesters are discussed, including birefringent layers present as an interphase between different layers. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 71: 1555–1562, 1999

Low styrene emission resins favoured for fibre-based composites

Low styrene emission resins favoured for fibre-based composites

LSE gel-coats lead resin developments at JEC

Low styrene emission resins have been around for a number of years. But until now the technology has proved difficult to transfer to gel-coats. This barrier now seems to have been broken. At JEC (Paris 24–26 April) three major resin producers launched LSE gel-coats. Amanda Weaver reports.

Resin Infusion under Flexible Tooling (RIFT): a review

Increasing legislation to limit styrene emissions (mainly from polyester resin systems) into the work place has been the key factor in promoting new technology in the manufacture of fibre reinforced plastics composites. Styrene emissions can be reduced by the development of: resin systems with low styrene emission; improved ventilation and air filtering systems; closed moulding techniques. It is the final area on which this paper concentrates. RIFT is a variant of vacuum-driven RTM in which one of the solid tool faces is replaced by a flexible polymeric film. The process is known by several acronyms—in this paper it is referred to as RIFT (Resin Infusion under Flexible Tooling). Potentially a very clean and economical composites manufacturing method, the process draws resin into a dry reinforcement on an evacuated vacuum bagged tool using only the partial vacuum to drive the resin. It reduces worker contact with liquid resin whilst increasing component mechanical properties and fibre content by reducing voidage compared to hand lay-up. For higher performance composites, RIFT offers the potential for reduced tooling costs where matched tooling (RTM or compression moulding) is currently used. This paper reviews the progress of RIFT from its first development as the Marco method in 1950 to the Seemann Composites Resin Infusion Manufacture Process (SCRIMP) today. Development of the process has been slow (compared to RTM) and generally lacking in scientific rigour. Current research is reviewed and the potential for scientific development is discussed.

Emission of Styrene during the Hand Lay-Up Molding of Reinforced Polyester

Abstract The emission rates of styrene monomer from standard and lowstyrene-emission (LSE) resins were determined during the hand lay-up molding of reinforced polyester. The evaporation tests were carried out in controlled laboratory conditions by using 0.165 m2 laminate. The emission rate was highest in the rolling phase, ranging from 59 to 79 mg/s/m2. The emission rate of styrene with LSE resin was 4-14 percent lower than that of standard resin. The use of LSE resin reduced the total evaporation of styrene 30-60 percent compared to standard resin. This is due to the fact that LSE resin has a lower evaporation rate in the period between the rolling and curing. The evaporation rates obtained by the gravimetric evaporation test do not include the rolling period and should not be used to estimate the emission rate of styrene in actual molding operations.