The Thermomechanical Processing Conditions and the Mechanical Properties of Injection Molded PP/PC Blends

2008 ◽  
Vol 587-588 ◽  
pp. 553-557
Author(s):  
Mariusz Krol ◽  
Marcin Bilewicz ◽  
Júlio C. Viana ◽  
Leszek Adam Dobrzański

This investigation aims at establishing the relationships between the thermomechanical conditions and the mechanical properties of a direct injection moulded polypropylene/polycarbonate blend (70/30wt composition). Rectangular plates (2 mm thick) were injection moulded by systematic variations of the processing conditions. The moulding programme was based on a design of experiments (DOE) approach, being considered variations in two levels of the melt (240 and 280°C) and the mould (5 and 80°C) temperatures and the injection flow rate (3.8 and 38 cm3/s). For comparison purposes, neat polypropylene was also moulded under the same set of processing conditions. In both cases the thermomechanical environment was characterised by computer simulations of the mould filling phase using commercially available codes (Moldflow). Tensile specimens were cut from the injected plates. The microstructure of the mouldings was characterized by polarized light microscopy, PLM. The mechanical characterization encompass the assessment of the tensile (at 5 mm/min at 23 °C) and impact toughness (unnotched Charpy test). The results are analysed by ANOVA. The presence of PC particles affects the crystallization of PP, this being revealed on the mouldings microstructures observed by PLM that are distinct for the neat and PP/PC blends. The mechanical properties are determined differently by the processing variables.

2017 ◽  
Vol 71 (5) ◽  
pp. 419-428
Author(s):  
Vesna Cvetkovic-Stamenkovic ◽  
Dragan Manasijevic ◽  
Sasa Marjanovic ◽  
Aleksandra Ivanovic ◽  
Biserka Trumic ◽  
...  

This paper deals with experimental and analytical investigations of the influence of thermomechanical processing conditions on the mechanical properties and electrical conductivity of PdNi5 alloy, in the form of wire ? 0.15 mm, for making catalysts-catchers. Obtained results showed that mechanical properties and electrical conductivity depend on the applied regime of thermomechanical processing. Knowing the dependence of influence of parameters of thermomechanical processing regime on these properties enables the production of PdNi5 alloy with required characteristics for use in the process of catalytic oxidation of ammonia, that is solving problems of loss of platinum metals, especially platinum. The results of analytical investigations of influence of thermomechanical processing regime, by software package SPSS, on tensile strength, elongation and electrical conductivity of PdNi5 alloy in the form of wire ? 0.15 mm showed that using a linear regression model the mutual influences of selected parameters of thermomechanical treatment on mechanical properties and electrical conductivity of PdNi5 alloy, can be adequately described and analyzed. The results showed that tensile strength and electrical conductivity were only slightly affected with a change of temperature and time of annealing while annealing time has significant influence on the elongation value.


2006 ◽  
Vol 514-516 ◽  
pp. 858-862 ◽  
Author(s):  
Marcin Bilewicz ◽  
Júlio C. Viana ◽  
António M. Cunha

This paper summarizes the processing, morphology and mechanical properties of PP/PCABS blend produced by a non-conventional injection moulding technique: shear controlled orientation in injection moulding, SCORIM. This technique consists on the in-mould shear manipulation of the melt during the solidification phase by using a special mounted mould plate equipped with two external hydraulic pistons. In this work attention is mainly concentrated on the effect of the processing conditions on the mechanical properties of 70/30 (%/w) PP/PC-ABS blend obtained by direct injection moulding. The SCORIM technique was used deliberately to induce a strong anisotropic character of this processed polymer-polymer composite that features a complex morphology, featuring outer highly oriented multi-layers and a less oriented core. Different settings of the operative variables were used according to the moulding program based on a design of experiments array (melt temperature, stroke time, number of strokes), assuring a wide processing window. The fracture surfaces of the mouldings were characterized by scanning electronic microscopy. The mechanical properties were assessed by tensile, flexural and fracture tests. The main significant processing variables determining the mechanical properties of the mouldings were identified together with their effects.


2020 ◽  
pp. 5-18
Author(s):  
D. V. Prosvirnin ◽  
◽  
M. S. Larionov ◽  
S. V. Pivovarchik ◽  
A. G. Kolmakov ◽  
...  

A review of the literature data on the structural features of TRIP / TWIP steels, their relationship with mechanical properties and the relationship of strength parameters under static and cyclic loading was carried out. It is shown that the level of mechanical properties of such steels is determined by the chemical composition and processing technology (thermal and thermomechanical processing, hot and cold pressure treatment), aimed at achieving a favorable phase composition. At the atomic level, the most important factor is stacking fault energy, the level of which will be decisive in the formation of austenite twins and / or the formation of strain martensite. By selecting the chemical composition, it is possible to set the stacking fault energy corresponding to the necessary mechanical characteristics. In the case of cyclic loads, an important role is played by the strain rate and the maximum load during testing. So at high loading rates and a load approaching the yield strength under tension, the intensity of the twinning processes and the formation of martensite increases. It is shown that one of the relevant ways to further increase of the structural and functional properties of TRIP and TWIP steels is the creation of composite materials on their basis. At present, surface modification and coating, especially by ion-vacuum methods, can be considered the most promising direction for the creation of such composites.


Metals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1094
Author(s):  
M. A. Lakhdari ◽  
F. Krajcarz ◽  
J. D. Mithieux ◽  
H. P. Van Landeghem ◽  
M. Veron

The impact of microstructure evolution on mechanical properties in superduplex stainless steel UNS S32750 (EN 1.4410) was investigated. To this end, different thermomechanical treatments were carried out in order to obtain clearly distinct duplex microstructures. Optical microscopy and scanning electron microscopy, together with texture measurements, were used to characterize the morphology and the preferred orientations of ferrite and austenite in all microstructures. Additionally, the mechanical properties were assessed by tensile tests with digital image correlation. Phase morphology was not found to significantly affect the mechanical properties and neither were phase volume fractions within 13% of the 50/50 ratio. Austenite texture was the same combined Goss/Brass texture regardless of thermomechanical processing, while ferrite texture was mainly described by α-fiber orientations. Ferrite texture and average phase spacing were found to have a notable effect on mechanical properties. One of the original microstructures of superduplex stainless steel obtained here shows a strength improvement by the order of 120 MPa over the industrial material.


2015 ◽  
Vol 659 ◽  
pp. 659-665
Author(s):  
Supakit Chuaping ◽  
Thomas Mann ◽  
Rapeephun Dangtungee ◽  
Suchart Siengchin

The topic of this research work was to demonstrate the feasibility of a 3D-MID concept using injection molding technique and investigate the effects of two weld line types on the structure and mechanical properties such as tensile, flexural strength and morphology. In order to obtain more understanding of the bonds between polymer and metals, two different polymer bases of polyphthalamide (PPA) with the same type and amount of filler content were produced by injection molding at the different processing conditions. A mold was designed in such a way that weld and meld line can be produced with different angles by changing as insert inside of the mold. The mechanical properties such as stiffness, tensile strength and flexural strength were determined in tensile and flexural tests, respectively. The results showed in line with the expectation of high reduction on mechanical properties in area where weld/meld lines occurred. The result of tensile test was clearly seen that weld and meld line showed a considerable influence on mechanical properties. The reduction in tensile strength was approximately 58% according to weld line types, whereas in flexural strength was approximately 62%. On the other hand, the effect of the injection times and mold temperatures on the tensile strength were marginal.


2017 ◽  
Vol 62 (4) ◽  
pp. 2125-2131 ◽  
Author(s):  
Z. Brytan

AbstractThe paper presents the results of the basic mechanical properties determined in the static tensile test, impact un-notched Charpy test and hardness of austenitic stainless steel type 316L produced by two techniques: classical pressing and sintering in a vacuum with rapid cooling and selective laser melting (SLM). In this work fracture surface of Charpy test, samples were studied.The results indicate that application of selective laser melting (SLM) makes it possible to double increase the strength properties of components manufactured from austenitic stainless steel type 316L compared to sintering in a vacuum. Resulted in mechanical properties strongly depend on porosity characteristic and the presence of superficial oxides in the case of sintered steel and the character of observed microstructural defects deriving from non-fully melted powder particles and the formation of voids between subsequently melted pool tracks during the SLM.


1995 ◽  
Vol 68 (2) ◽  
pp. 267-280 ◽  
Author(s):  
A. I. Isayev ◽  
J. Chen ◽  
A. Tukachinsky

Abstract A novel patented process and several reactors have been developed for devulcanization of waste rubbers. The technology is based on the use of the high power ultrasonics. The ultrasonic waves of certain levels in the presence of pressure and heat rapidly break up the three-dimensional network in crosslinked rubbers. The devulcanized rubber can be reprocessed, shaped and revulcanized in much the same way as a virgin rubber. The first laboratory reactor has been scaled up to pilot-plant level by the National Feedscrew and Machining, Inc. Various devulcanization experiments were carried out with model styrene-butadiene rubber (SBR) and with ground rubber tire (GRT). Curing behavior, Theological properties, and structural characteristics of rubbers devulcanized at various processing conditions were studied, as well as mechanical properties of revulcanized rubber samples. A possible mechanism of the devulcanization is discussed. The performed measurements indicate that the rubbers are partially devulcanized, and the devulcanization process is accompanied by certain degradation of the macromolecular chains. In spite of these observations, the processing conditions are identified at which the retention of the mechanical properties is found to be good. A further work is in progress to find the optimal conditions of devulcanization and to improve the selectivity of the process towards breaking up the chemical network only.


Polymers ◽  
2018 ◽  
Vol 10 (7) ◽  
pp. 779 ◽  
Author(s):  
Emanuele Parodi ◽  
Gerrit Peters ◽  
Leon Govaert

The effect of processing conditions during injection on the structure formation and mechanical properties of injection molded polyamide 6 samples was investigated in detail. A large effect of the mold temperature on the crystallographic properties was observed. Also the the effect of pressure and shear flow was taken in to consideration and analysed. The yield and failure kinetics, including time-to-failure, were studied by performing tensile and creep tests at several test temperatures and relative humidities. As far as mechanical properties are concerned, a strong influence of temperature and relative humidity on the yield stress and time-to-failure was found. A semi-empirical model, able to describe yield and failure kinetics, was applied to the experimental results and related to the crystalline phase present in the sample. In agreement with findings in the literature it is observed that for high mold temperatures the sample morphology is more stable with respect to humidity and temperature than in case of low mold temperatures and this effects could be successfully captured by the model. The samples molded at low temperatures showed, during mechanical testing, a strong evolution of the crystallographic properties when exposed to high testing temperature and high relative humidity, i.e., an increase of crystallinity or a crystal phase transition. This makes a full description of the mechanical behavior rather complicated.


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