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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REVIEW OF PE PIPE LIFETIME PREDICTION BASED ON PENT TEST
A new method of evaluating polyethylene (PE) pipe brittle failure time has been recently proposed. The method consists of an extrapolation of the failure time in standard PENT test to brittle failure time of PE pipes of arbitrary diameter and wall thickness at various loads and temperatures. The method is based on several assumptions that have not been adequately addressed in . This paper presents a detailed review of the theoretical and experimental basis of the extrapolation proposed in  and reveals its limitations. A fracture mechanics analysis of the PENT test is presented. It requires evaluation of parameters in power law" equation of the slow crack growth (SCG). Thus a specimen whose stress intensity factor (SIF) is independent of crack length has been used to serve this purpose. Such specimen allows an accurate determination of crack growth rate vs. SIF relationship and thus predicts the duration of SCG stage of brittle fracture process at various temperatures. The study indicates that the formula proposed in  can be used for materials ranking with respect to SCG resistance within a limited temperature range but is inadequate for estimation of lifetime in brittle fracture."
INFLUENCE OF PROCESSING PARAMETERS ON MICROSTRUCTURE AND PROPERTIES OF A POLYETHERIMIDE JOINED BY FRICRIVETING: INVESTIGATION OF ROTATIONAL SPEED
FricRiveting is a new and promising spot joining technique for polymer-metal structures recently introduced at ANTEC 08. It is well known that processing in joining technology plays a central role in dictating joint properties and so understanding it is important for producing reliable connections. Rotational speed is an important controlling parameter in FricRiveting. This study experimentally determines the influence of rotational speed on FricRiveting’s joint microstructure local and global strength and thermal history for a thermoplastic polyetherimide joined by threaded aluminum rivets.
INFLUENCE OF PROCESSING PARAMETERS ON MICROSTRUCTURE AND PROPERTIES OF A POLYETHERIMIDE JOINED BY FRICRIVETING: INVESTIGATION OF ROTATIONAL SPEED
FricRiveting is a new and promising spot joining technique for polymer-metal structures, recently introduced at ANTEC 08. It is well known that processing in joining technology plays a central role in dictating joint properties and so understanding it is important forproducing reliable connections. Rotational speed is an important controlling parameter in FricRiveting. This study experimentally determines the influence of rotational speed on FricRiveting's joint microstructure,local and global strength, and thermal history for a thermoplastic polyetherimide joined by threaded aluminum rivets.
CURE KINETICS OF POLY (PHENYLENE ETHER)/EPOXY RESIN SYSTEM
The cure kinetics of poly(phenylene ether)/epoxy resin (PPE/EP) cure system was investigated by using an advanced isoconvensional method (AICM). The curing experiments of PPE/EP cure system with different PPE/EP ratios were carried out by means of nonisothermal differential scanning calorimetry (DSC) with different heating rates of 5, 10, 15 and 20 oC/min. From the DSC curves it can be shown that the curing mechanism of PPE/ER is so complicated that PPE content effects most cure kinetic parameters. A variation of the effective activation energy with the extent of conversion was obtained by AICM and analysized.
STUDY ON THE IN-MOLD PUNCHING OF THE THERMOPLASTIC INJECTION MOLDING
An in-mold punch device was designed; the shear break mechanism was installed in the position of the holes of the product. The surface of the product is integrated during the plastic injection forming process; therefore, no appearance defect like weld lines will occur. Experimental results showed that lower processing temperature and faster shear velocity are helpful to reduce the difference between the punch dimension and the hole dimension. The shorter cooling time is advantageous for the product shrink; while if the point is the smoothness of the circular hole; the correct way is to enhance the punch velocity and prolong the cooling time.
COMPONENT MICRO - INJECTION MOLDING TECHNOLOGY FOR MANUFACTURING OF HIGH PRECISION MICRO PARTS: A SYSTEMATIC PROJECT APPROACH
The project set itself the goal of the new possibilities of micro-injection molding of shotweight-optimized two component micro parts in regards of quality, flexibility and cost, including in-line measurement and testing with the stages of assembly, handling and logistics in the territory of the production of micro-optical systems. Based on the new machine concept of a two-component micro ƒ?? injection machine (2C-?¬IMM) a flexible and compact example of supply chain for the production of reliable optical systems were developed. The process chain contains the technologies of high precision micro injection molding technology, quality-control by optical control and geometric dimension and shape measurement, separation procedures of the runner and further assembly steps. A process-handling technology with special grippers combines and automates the individual process steps. An optoelectronic sensor, and an application with microfluidic functions for Biotechnology (so called Demonstrators) were selected to test the developed system. In both cases, all stages of product development from product design to be included on replication by injection molding, assembly and integration of handling opereations of the components had to be evaluated. The development of a scalable manufacturing technology for both examples is essential, and will be pursued as a priority. The project provides a variety of results: A novel, multiflexible manufacturing plant for the production of future-oriented products, innovative individual modules, new and improved production methods and advanced microoptic products.
NAVIGATING SYSTEM FOR HOT-RUNNER DESIGN WITH KNOWLEDGE MANAGEMENT
Hot-runner is getting more popular in injection molding process especially for the high surface-quality product. This work is to develop a navigating system for the hot-runner design with knowledge management. This web-based system provides step-by-step functions to guide the user through the sub-processes of product specification, manifold design, component assembly, spacer design and cylinder plate. Moreover, the knowledge database provides easy access of standard components which can be assembled automatically or semi-automatically. The system can provide the proven 3D hot-runner design with much shorter time.
EFFECT OF ORGANOCLAY ON THE MECHANICAL / THERMAL PROPERTIES OF MICROCELLULAR INJECTION MOLDED PBT-CLAY NANOCOMPOSITE
An organically modified montmorillonite (MMT) was compounded with Polybutylene Terephthalate (PBT) in a twin-screw extruder. The organoclay PBT nanocomposites were then injection molded by conventional and microcellular methods. Nitrogen was used as the blowing agent. The effect of organoclaycontent, organoclay size (8 and 35 ?¬m), and speed of thescrew (80 and 100 rpm) on the mechanical and thermal properties were investigated.The results showed that when the MMT content was 1.0 wt%, the nanocomposites have maximum tensile strength, wear resistance, and cell density. Moreover, the larger the particle size, the greater the tensile strength. The screw speed during compounding also affected the mechanical strength. The higher speed of the screw increased the tensile strength of the nanocomposites. The addition of MMT also helped the thermal stability of the PBT/Clay nanocomposites. The WXRD results showed that when MMT loading is 1.0 wt%, the nanocomposites have maximum d-spacing structure. TEM results showed that MMT is well dispersed on the nanocomposites at a MMT loading of 1 .0 wt%.
DESIGN AND THEORETICAL ANALYSIS OF MINI-PLUNGER SPRAYER USED IN SW2502 FUSED DEPOSITION MODELING RAPID PROTOTYPING SYSTEM
The fused deposition modeling rapid prototyping system is based on the manufacturing principle of layer by layer. The sprayer is the key component. Based on the polymer rheological properties, the structure design and theoretical analysis of the mini-plunger sprayer of SW2502 fused deposition modeling system are studied. The plasticizing capacity of the mini-plunger sprayer is analyzed in theoretically. It is very important for the fused deposition modeling process to maintain a stable plasticizing capacity. The driving force of ABS feed is related to several parameters such as structure form of sprayer and material property, etc. The barrel and nozzle design should be fit for mobility, purity, and mechanical property of ABS feed. The modified ABS feed adopts self-pressure-adding driving method to decrease the pressure losses of barrel and nozzle. The plasticizing capacity of the sprayer is more than 20g/h.
PROCESSING COSTS AND ENVIRONMENTAL IMPACT OF BIO-PLASTICS
This work studied bio-plastics such as polylactic acid (PLA) and protein based plastics form corn and compared to petroleum based plastics such polyethylene (PE) and polystyrene in terms of their ecological as well as economical performance from a “Cradle to Grave” perspective. This study included energy input emissions output of green house gases and costs from their life cycle steps of raw material acquisition to the final product disposal. It was found that products manufactured from bio-based feedstocks were relatively higher in cost they resulted in less green house gas emissions.
VIRTUAL SIMULATION OF TOP LOAD PERFORMANCE OF PLASTIC BOTTLES
A novel analytical computational model was developed to predict Top Load and Side Load performance of oval containers. The performance of oval and other non round containers is dependent on the thickness distribution achieved during blow molding. Simulating blow molding and performance of containers using Virtual Prototypingƒ?› Software and feeding the input for Finite Element Analysis provides an accurate mechanism to predict container performance. A 24oz. generic oval container with aspect ratio of 1.58 was simulated for empty and filled top load performance. A critical part of blow molding oval containers is the ability to achieve a more uniform thickness profile along the circumference of the container at any given height. This isachieved by using preferential heating where the infra-red?ÿ heating ovens have special slotted reflector plates that allow the preform to be heated differently 90?ø apart. For the 24oz. oval container with a high aspect ratio it was observed that the use of preferential heating is necessary to achieve uniform thickness distribution in the range of 0.3mm-0.4mm. A non preferentially heated preform resulted in container thickness being 0.4-0.6mm in a concentrated region adjoining the minor axis. The preferentially heated performs resulted in containers having better empty and filled Top load. The side grip load was the only performance characteristic that was higher for the non preferentially heated containers but that works only in a small region and the non uniformity of thickness makes the container not aesthetically pleasing and would not be acceptable in a production process due to inconsistency in material distribution.
EPOLYPROPYLENE - CUP CONVERSION FROM INJECTION MOLDING TO THERMOFORMING
Food containers such as cups can be made by injection molding (IM) or thermoforming (TF). Typical materials are high density polyethylene (HDPE) polypropylene (PP) and high impact polystyrene (HIPS). For many years the preferred choice for polypropylene cups was IM because it produces a high quality part with excellent part-to-part consistency. Conventional TF to make similar containers in PP results in wider dimensional tolerances. On the other hand in-line trimin- place thermoforming overcomes many of the limitations of conventional TF and allows for the production of high quality containers. This paper outlines the conversion from IM to trim-in-place for a 235-ml cup and compares the physical properties of cups from each process.
THE IMPORTANCE OF MOLD TEMPERATURE ON THE PROPERTIES OF POLYPHENYLENE SULFIDE PARTS
Polyphenylene Sulfide (PPS) is a semi-crystalline engineering thermoplastic recognized for its unique combination of properties including chemical resistance, dimensional stability and thermal stability. The exceptional performance of this material in these environments has lead to extensive use in automotive ƒ??under the hoodƒ? applications. To maximize these material properties and make the high quality parts demanded by the automotive industry, it is very important that certain guidelines are followed in the molding process, failure to do so can result in premature part failure. This paper outlines one of the basic molding requirements, mold temperature, and the effect it has on the finished part.
ENHANCING BIOPOLYMERS WITH HIGH PERFORMANCE TALC PRODUCTS
The effect of talcs on PolyLactic Acid (PLA) performance has been studied with a focus on properties of fully crystallized PLA. The results show that talc could be used as an effective nucleation agent to improve mechanical properties of PLA including stiffness, heat deflection temperature and impact strength. It is shown that optimum crystallization of PLA could result in a maximum impact performance that is independent of the type of talc if complete crystallization is achieved. However, utilizing high performing talc such as the high-aspect ratio Luzenac HAR?? talc could allow maximum impact performance of crystallized PLA to be achieved at lower talc loading. It is also shown that the addition of plasticizers and impact modifiers could further improve impact properties through modifying the amorphous phase of PLA.
MODIFIED POLYETHYLENE FOR IMPROVED ADHESION PROPERTIES IN ROTATIONALLY MOLDED PARTS
Rotationally molded polyethylene parts filled with polyurethane foam have been used for various applications in different marketplaces worldwide. However one of the main deficiencies of these two-component parts is a weak interface between both materials which often causes delamination of the polyurethane foam from the polyethylene skin.New polyethylene powders, developed by ICO Polymers using a unique and innovative low pressure plasma technology, successfully overcome the issues related to poor PE/PU foam adhesion without any modification to the current molding practices used by molders.An introduction to the technology, along with actual results achieved by the use, will be presented.
THE RESEARCH OF REDUCE RESIDUAL STRESS OF POLYCARBONATE PRODUCTS BY HEAT TREATMENT
As a kind of thermoplastic with excellent performance, polycarbonate is an ideal substitute for traditional glass applied in many optical products for its lightness and good transparency. Most of the products are made by injection molding, but yield of the products couldn't be improved for the problems on residual stress.Transparent polycarbonate will be used in the experiments; photoelasticity is to be used to calculate residual stress of specimen. The results indicate that residual stress decreases as the heating time increases during the heat treatment. In addition, thickness of specimens also may exert an influence on the effect of heat treatment.
INNOVATIVE PVD TECHNOLOGY SUSTAINABLE METALLIZATION PROCESSING WITH ADVANCED FUNCTIONALITIES FOR PLASTIC SURFACES
The continuing trend toward metallic surfaces on plastics has motivated hartec to further develop PVD metallization by magnetron sputtering.Specifically, the combination of PVD + Topcoat (paint) appears to be a viable alternative to electroplated surfaces and real metals. Ecologically, the PVD process is sustainable, 100% non-toxic and emission free.PVD metallization offers a wide range of applications with advanced functionalities: Daynight design realized by laser-etching; optically and electromagnetically translucent coatings for 'hidden' displays and sensor technology; flexible substrates like TPU or TPE, for example used for safety components like airbag emblems in the automotive industry etc.
A STUDY OF THE FREEZING PHENOMENA IN PVC AND CPVC PIPE SYSTEMS
Residential and commercial piping systems often experience complex failures from freeze events. In this paper the freezing failures are studied by replicating pipe freezing conditions in a laboratory setting. Testing was performed on ?« inch (12.5mm) PVC and CPVC pipes. Pressure and temperature during the freeze event were monitored and the fracture modes of failed pipes were examined. Freeze events result in excessively high pressures. It has been shown that during a freeze event, the properties of plastic pipes are advantageous over other more rigid piping systems. In this study, it was observed that PVC and CPVC pipes were able to sustain over thirty times the typical household water pressure before bursting occurred.
VALIDATION OF IN-MOLD SHRINKAGE SENSOR FOR DIFFERENT CAVITY THICKNESSES
An in-mold shrinkage sensor having a deflectable diaphragm under melt pressure, instrumented with strain gages connected in a full bridge circuit is designed and validated for conventional and thin wall parts. Molded part shrinkage is then measured as the polymer melt solidifies, shrinks, and retracts from the mold wall. The DOE was conducted using HIPS to validate the sensor performance for the thickness of 2.5 mm and 1.5 mm. With a 2.5 mm and 1.5 mm cavity thickness, the coefficient of correlation, R2, to the final part thickness was 0.939 and with 0.966 respectively for the in-mold shrinkage sensor.
DILUENT EFFECT OF THE POLY(ETHYLENE-alt-PROPYLENE) (PEP) BLOCK UPON THE POLYETHYLENE (PE) THERMAL FRACTIONATION OF PE-block-PEP DIBLOCK COPOLYMERS
The diluent effect of the amorphous (rubbery) PEP block upon the SSA thermal fractionation of the PE component as compared with the PE homopolymer was evaluated. The shape and distribution of the melting peaks obtained after applying the SSA protocol is notably different in the PE-b-PEP diblock copolymers. It has been established how the presence of a diluent blended with the amorphous zones of this semicrystalline polymer trends to increase the molecular mobility of PE chains in such a way that fractions closer to thermodynamic equilibrium can be generated.
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