SPE Library

The SPE Library contains thousands of papers, presentations, journal briefs and recorded webinars from the best minds in the Plastics Industry. Spanning almost two decades, this collection of published research and development work in polymer science and plastics technology is a wealth of knowledge and information for anyone involved in plastics.

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Conference Proceedings

Barrier Coating of Flexible Substrates

W. Michaeli | Ch. Hopmann | P. Awakowicz | K. Bahroun | S. Steves | H. Behm | F. von Fragstein, November 2011

In the presented project a new coating plant for large area microwave (2.45 GHz) excited low pressure plasma coating with substrate bias has been designed, which allows the coating of foils up to a size of 300 * 300 mm². The objective of the research work is to characterize the effects of the process parameters on the properties of plasma-polymerised coatings, particularly regarding their behaviour under strain. Investigations are carried out using a microwave plasma source and polyethylene terephthalate (PET) as substrate material. As layer forming monomers for plasma polymer barrier coating of the substrates are used.

NEW STRUCTURAL BIOCOMPOSITES FOR CAR APPLICATIONS

Jiying Fan | Elias Nassiopoulos | James Brighton | Alain De Larminat | James Njuguna, November 2011

Recently advances in research and manufacturing techniques of biocomposites have allowed the car manufactures to use bio-composite in various applications. Biocomposites are fast emerging as viable alternative to traditional materials due to their low cost, lightweight, good mechanical performance and biodegradable properties. ECOSHELL project (Development of new light high-performance environmentally benign composites made of bio-materials and bio-resins for electric car application) proposes to achieve a full bio-composite made of high performance natural resins matrices, resulting in the use of totally natural, environment friendly composites, with enhanced strength and bio-degradability characteristics designed for the electric car.

THE PRODUCTION AND USE OF SUPPORTED NANO-SILVER PARTICLES IN POLYMER SYSTEMS

Matthew Gande | Ryan Fenton | Urs Stadler | Sungyeun Choi, November 2011

Silver is a known antimicrobial agent, and has found use in protecting a range of products against bacterial growth. The inherently large surface area of silver nanoparticles allow for a high release rate of silver ions to the environment, where they can be active against a wide range of microbes. Herein, we report a new method of producing silver nanoparticles using a plasma furnace. This process easily allows for the support of the nano-silver material on micron-sized inorganic particles. Silver formed in this manner is more easily dispersed in polymer systems, while maintaining antimicrobial activity against gram positive and negative bacteria.

Proposed UV Rating Method for UV Stabilized Injection Moulding Polyethylene

J. D. Ratzlaff, November 2011

The European injection moulding market is filled with numerous injection moulding resins that claim resistance to ultraviolet light from outdoor exposure. However, few, if any, have actual comparable data that allows a buyer to distinguish the performance of one resin to another. Likewise, if artificial weathering results are given, how does this relate to actual outdoor performance? Can a relation to outdoor performance be translated to geographic variances in weather? This paper gives a summary of several published artificial ultraviolet exposure studies, some known standards with industry acceptance and how the tests relate to outdoor exposure with a concise experiment between two UV test methods. Finally, a proposal is given of standardized ultraviolet resistant testing for the injection moulding world of polyethylene. This includes estimating outdoor performance with the variances of solar radiation based on geography.

Material Handling and Blending Systems for Molding and Extrusion

Keith Larson, November 2011

Molding and extrusion lines rely on the auxiliary equipment that works with them. This equipment supplies the regrind, resin and additives, cools the process, maintains critical temperatures and even monitors the entire operation. Inadequate process cooling, material handling or size reduction equipment can cause many problems, including the following:; Inadequate process cooling can reduce product output; Poor temperature control can cause product quality issues; Material can be contaminated if not handled and stored properly; The output of the line can be reduced, and even interrupted, if the material is not conveyed to the extruder at the required rate; Product quality will suffer if the material is not blended and metered into the extruder throat at the correct ratios; Excess dust caused by poor size reduction equipment can create processing problems. The following auxiliary equipment is crucial to any molding or extrusion process, and needs to be taken into consideration:; Cooling tower system; Chilled water system; Temperature control units; Bulk storage of the raw material; Material conveying system; Blending and feeding equipment; Crystallizing and drying systems; Size reduction systems. This paper will focus on material handling and blending systems – the other areas will be discussed at a later time.

STRAIN HARDENING: AN ELEGANT AND FAST METHOD TO PREDICT THE SLOW CRACK GROWTH BEHAVIOR OF HDPE PIPE MATERIALS

D.J.M. (Linda) Havermans – van Beek | Rudy Deblieck, November 2011

Resistance to slow crack growth is an important material property of polyethylene which determines the application lifetime, especially for utility pipe applications. Usually, the slow crack growth resistance of materials is accessed by time consuming testing methods such as NPT, FNCT, PENT, etc. These methods require often the use of notched samples, the use of specific fluids (e.g. detergents) and elevated temperatures. Here we present the outline and validation of an elegant method to predict slow crack growth resistance in materials in a simple, accurate and fast way. The resistance to slow crack growth is predicted from a simple tensile measurement at 80 C. It will be shown that the slope of the stress-strain curve above the natural draw ratio (i.e. the strain hardening regime) correlates very well with the results obtained by the full notch creep test (FNCT), Notch Pipe Test (NPT) and the stress intensity ranking of the cyclic loaded Cracked Round Bar test (CRB) of the same materials. This strain hardening method is elegant in that it does not require notched specimen and/or detergents. Besides the advantage that the method is easy to implement in laboratories, its main advantage is the dramatic decrease of measurement times from thousands of hours to only a few. This method is very suitable in the development of new grades, but also very valuable as a batch release test for both resin suppliers and pipe converters.

TOUCHNESS OF MICROCELLULLAR POLYCARBONATE FOAMS AND IT’S DEPENCE OF THE TEMPERATURE

Hans-Peter Heim | Martin Rohleder | Andrzej K. Bledzki, November 2011

This investigation analyses the notched impact strength of microcellular polycarbonate which was produced by injection molding using physical blowing agents. By varying different processing parameters, such as blowing agent concentration or the injection velocity, injection moulded plates were produced and characterized with regard to morphology and the Charpy notched impact strength. A temperature-dependent analysis concerning the correlation between the foam morphology and the notched impact strength was carried out. Additionally investigations were performed to find out if the failure mechanisms, which occur at low temperatures, also function the same when exposed to temperatures higher than 80°C.

Sustainability with Automotive Carbon Fibre Composites: Reclaimed Carbon Fibre — cPBT Thermoplastic Composite

Jackie Rehkopf, September 2011

PowerPoint Presentation at Automotive Composites Conference and Exhibition

Thermoplastic Overmolded Continuous Fiber Structures

Kipp Grumm, Amit Kulkarni, September 2011

PowerPoint Presentation at Automotive Composites Conference and Exhibition

Design and Fabrication of a Structural Composite Automotive Underbody

Libby Berger, September 2011

This paper describes the design and fabrication of a structural composite underbody by the Automotive Composites Consortium. This includes material and process development joint methodology and design design of the component manufacture and design scenario and initial fabrication of the underbody.

Properties and Molding of a Fabric SMC for a Structural Composite Automotive Underbody

Libby Berger, September 2011

The glass fabric SMC developed by the Automotive Composites Consortium for a structural composite underbody was compounded molded and characterized for material and thermal properties and NDE techniques evaluated for damage inspection.

Mechanical & Impact Response of Recycled Thermoplastic & Flyash Foam Composites

Uday Vaidya, September 2011

The heavy transport industry has a significant amount of scrap generated in the manufacture of parts such as trailer bodies and structural components. Presently that scrap is landfilled. This paper presents the processing and resulting properties of recycled thermoplastic composites into useful products for reuse in transportation and related applications.

ANALYSIS OF POLYPROPYLENE ODOR BASED ON ELECTRONICOLFACTORY SYSTEM

Jin Yan, Kang Peng, Li Xue, September 2011

In this paper the undesirable odor from virgin PP resin was studied using an electronic olfactory system equipped with a set of metal oxide semi-conductor sensors. Odor of PP resin and the effects of heating temperature and heating time on the odor from different grades of PP resin were studied. It was found that the odor of PP resin was detected by the electronic olfactory system. Effects of heating temperature above 50 °C and heating time on the release of the odor were obviously observed and the odor intensity increased with the increase of heating temperature and the extension of heating time.

Integration of Features into Parts Made from Thermoplastic Unidirectional Tape — Overview and Case Study

Benjamin Hangs, September 2011

Thermoplastic composite materials have lately been considered increasingly for application in structural components. Especially semi-finished products with continuous fiber-reinforcement such as woven fabrics or unidirectional tapes have a high potential to increase part performance significantly. However due to their limited drapability and flowability the forming of highly complex structures such as ribs is not feesible. This paper presents an overveiw of desired features that are commonly part of complex technical applications. It shows how implementation of those can be achieved with continuous-fiber-reinforcement structures by combining them with short and long fiber-reinforcement material. The subsequent case study presents a related investigation on overmolding of unidirectional tape inserts. In conclusion an outlook is given on how these results can be transferred to more complex components.

Program Summary of the ACC Automotive Composites Underbody

Libby Berger, September 2011

A structural composite underbody capable of carrying crash loads has been designed fabricated assembled into a structure and tested by the Automotive Composites Consortium. The underbody is compression molded of sheet molding compound (SMC) with a vinyl ester matrix and predominately glass fabric reinforcement with some chopped glass. CAE-based design methodologies were utilized to assess the structural stiffness and impact performance of the initial composite underbody design. Weld bonding was selected as the means to join the composite underbody to the steel passenger compartment. A method for weld bonding the structural composite has been developed and tested in static and dynamic modes. The molded underbody was tested in modal bending and torsion. The underbody was assembled into a structure mimicking an automotive body-in-white and tested to simulate an offset deformable barrier crash. The Automotive Composites Consortium (ACC) is a joint program between GM Ford Chrysler and is funded in part by the United States Department of Energy.

Manufacturing Scenarios & Challenges with a Fabric SMC Automotive Underbody

Charles Knakal, September 2011

Compression molding of fabric SMC in steel tooling is a cross between prepreg molding and regular sheet molding compound (SMC) molding. Material processing differences such as minimal material flow represent major manufacturing challenges requiring different approaches for production operations. This paper will present the observed challenges and potential approaches that will enable cost effective manufacturing scenarios. Aspects of the processing include (but are not limited to) SMC compounding charge cutting charge placement tool loading edge filling of the part wrinkles and overlaps part trimming modeling and material testing. Presented will be solutions we utilized in addition to studies and cost models used to alleviate some concerns.

Enabling Faster Resin Infusion Processing of Automotive Composites: A Nano-Nectar" Technology Leading Epoxy to High Performance and Low Viscosity "

W.H. Katie Zhong, September 2011

Graphitic carbon nanofibers (GNFs) were first made into a “nano-nectar” which is “liquid nano-reinforcement” (LNR) with reactive nanofibers (r-GNFs). Due to the uniform dispersion of r-GNFs in the LRN simply mixing the LNR with an epoxy led to a nano-modified epoxy with uniform dispersion of nanofibers a so-called nano-epoxy. More importantly the nanofibers were involved in the cross-linking structures of the epoxy through covalent bonding between the epoxy matrix and the nanofibers. Results showed that the nano-epoxy possesses dramatically reduced viscosity and enhanced multiple mechanical and thermal performances by simply mixing two kinds of liquids: a very small amount of LNR functioning as a “nector” and a base epoxy matrix. The simplicity of the “nano-nectar” approach leading to reduced viscosity (e.g. 50% lower than the pure epoxy) can lead to faster Resin Infusion processing for automotive composite manufacturing due to reduced power requirements for flow and part consolidation.

Material Properties of a Fabric Sheet Molding Compound for a Structural Composite Underbody

Libby Berger, September 2011

The Automotive Composites Consortium (ACC) has selected a fabric sheet molding compound (SMC) as the main material and process system for a structural composite underbody. This Paper describes the properties of this SMC material including tensile compression and flex. Thermal properties including coefficient of linear thermal expansion and Tg temperatures were determined. The effect of two different fabric weights and several layups thicknesses and molding parameters is also reported. Overlap and butt joints within the layup were compared. The Automotive Composites Consortium is a joint program between General Motors Ford Chrysler in partnership with the United States Department of Energy.

Double Dome Structural Test—Analysis Correlation Studies

Hannes Fuchs, September 2011

Computer-aided engineering-based design methodologies have been utilized throughout the Automotive Composites Consortium Focal Project 4 to assess the vehicle level structural stiffness and impact performance of the composite underbody design proposals and to estimate the potential mass reduction for several candidate material scenarios. To increase confidence in the vehicle-level model predictions and to better understand the effect of fabric draping on fiberglass fabric Sheet Molding Compound composite material properties several quasi-static structural “double dome” component tests were simulated for the purpose of test-analysis correlation and modeling methodology development.

Fatigue Performance of SMC Composite Material Under Different Environmental Damage & Temperature Conditions

Justin Hunt, September 2011

The Automotive Composites Consortium (ACC) a partnership of Chrysler Group LLC Ford Motor Company General Motors Company and the U.S. Department of Energy conducts pre-competitive research on structural and semi-structural polymer composites to advance high strength lightweight solutions in automotive technology. An ACC focal project concerning the development of a structural composite underbody was established to provide methodologies and data for each ACC member company to implement lightweight cost-effective structural composites in high volume vehicles. This objective will be fulfilled through design analysis fabrication and testing of a structural composite underbody. A key design element required for implementation of the underbody structure is an understanding of the affects of environmental temperature and impact damage on the axial fatigue performance of the SMC composite material selected for the underbody structure fabrication. Research efforts have been made on fatigue performance of different type of composite materials (Ref. 1-5). In this study specimens were tested with no damage as well as two levels of impact damage. Environmental temperatures for the undamaged specimens were -40°C 21°C and 80°C. It was observed that fatigue life increased at low temperature conditions and decreased at high temperatures. The affect of temperature had a greater influence on fatigue life than the impact damage in this study. Temperature increases as measured at the specimen surfaces were observed as test frequency increased. Similar observations were made by Bellenger et al (Ref.6). The relationship between stress loading frequency and temperature will be investigated. Optical and scanning electron microscopy will be used to examine the crack locations and characteristics for specimens tested under different conditions.