Research on Hygrothermal Aging of Dynamic Injection Molded Polypropylene Products

2010 ◽  
Vol 447-448 ◽  
pp. 391-395
Author(s):  
Bin Liu ◽  
Sheng Jin Wu ◽  
Qing Hui Liu ◽  
Jin Ping Qu
Keyword(s):  
Injection Molding ◽  
Test Chamber ◽  
Accelerated Aging ◽  
Molding Machine ◽  
Hygrothermal Aging ◽  
Accelerated Aging Test ◽  
Aging Test ◽  
Aging Properties ◽  
Before And After ◽  
Injection Molded

The polypropylene products are injection molded by the dynamic injection molding machine. The performance characteristics of polypropylene products under steady and dynamic injection molding are gained by the DSC indicating methods. Accelerated aging test with hygrothermal test chamber (the aging temperature is 90°C, and the humidity is 95%) is conducted in the study. The regularity for impact strength property of polypropylene is studied during the test in contrast. The change of carbonyl content in the polypropylene products is analyzed both before and after aging by FTIR. The results show that the dynamic injection molding could significantly improve the anti-hygrothermal aging properties of the polypropylene products.

scholarly journals Artificial and Natural Aging of Polypropylene Used in Passenger Vehicle Bumpers

2021 ◽  
Vol 58 (2) ◽  
pp. 201-210
Author(s):  
Hongshen Zhang ◽  
Hongfei Zheng
Keyword(s):  
Accelerated Aging ◽  
Natural Aging ◽  
Short Term ◽  
Uv Aging ◽  
Accelerated Aging Test ◽  
Aging Test ◽  
Wide Range ◽  
Aging Properties ◽  
Materials Used ◽  
The Impact

Polypropylene (PP) has a wide range of applications in the automobile bumpers due to its many excellent properties. Mechanical properties of PP for automobile bumpers are investigated through an artificial accelerated aging test. The aging rules after different years of normal use and the artificial accelerated aging test are analyzed. The correlation between natural and artificially accelerated aging is also explored. It provides a reference for the study of the aging properties of polymers for automotive applications. Results show that the UV aging test can effectively simulate changes in tensile and bending strengths after natural aging and can be used to evaluate the weathering resistance of PP materials used in automotive bumpers. The tensile and bending strengths of these materials remain good during aging, and elongation is sensitive to aging. The short-term artificial accelerated aging test does not exert a significant influence on the impact strength of materials, and artificial accelerated aging does not completely reproduce the aging process of the material.

Corrosion resistance of hoisting ropes

2020 ◽  
Vol 62 (12) ◽  
pp. 1173-1180
Author(s):  
Haşim Fırat Karasu ◽  
Mine Demirsoy
Keyword(s):  
Corrosion Resistance ◽  
Aging Process ◽  
Steel Wire ◽  
Accelerated Aging ◽  
Electrochemical Test ◽  
Accelerated Aging Test ◽  
Aging Test ◽  
Different Types ◽  
Before And After ◽  
The Impact

Abstract In this study, the goal is to determine the types of steel rope best used in environments such as harbors and on ships, by examining the behavior of different types of steel wire hoisting ropes used in cranes with respect to corrosion. Initially, hemp and steel wire core ropes were taken from 6 × 19 Standard, 8 × 19 Seale and 6 × 36 Warrington Seale rope groups that have the same diameter. Corrosion resistance was compared in these ropes through the application of three methods. According to the first method, corrosion resistance was examined via change in material mass. For this purpose, ropes were subjected to an accelerated aging test in an aging test cabin in accordance with ASTM B117 standard for one month for each aging process. 3 different 30-day processes were followed with 24-hour cycles. Corrosion exposure rates differed for each process. After going through the aging process, the damage suffered by the ropes was determined via visual inspection and the impact left by corrosion was evaluated by examining the mass changes seen in the ropes before and after aging for each process. The Tafel extrapolation, which is an electrochemical test, was applied in the second method. Ecorr and Icorr values of the ropes as well as their corrosion rates were determined and compared. Corrosion behavior was investigated in the third method through the application of mechanical experiments on aged steel ropes. In conclusion, corrosion resistant hoisting ropes were identified by comparing the results attained from the three methods.

scholarly journals ACCELERATED AGING OF Piptadenia moniliformis (BENTH.) SEEDS

2018 ◽  
Vol 31 (3) ◽  
pp. 681-686
Author(s):  
GUTIERRES SILVA MEDEIROS AQUINO ◽  
CLARISSE PEREIRA BENEDITO ◽  
KLEANE TARGINO OLIVEIRA PEREIRA ◽  
PAULO CÉSAR DA SILVA SANTOS ◽  
JÉSSICA CHRISTIE DANTAS DE OLIVEIRA
Keyword(s):  
Seedling Emergence ◽  
Accelerated Aging ◽  
Dry Mass ◽  
Accelerated Aging Test ◽  
Aging Test ◽  
Before And After ◽  
Physiological Quality ◽  
Suitable Combination ◽  
Different Levels

ABSTRACT The accelerated aging test consists of evaluating the vigor of the seeds under conditions of high temperature and humidity, with the purpose of identifying the physiological quality of lots with similar germination. The objective of this study was to evaluate the efficiency of the accelerated aging test for classifying seed lots of P. moniliformis at different levels of vigor. Initially, the seed lots were assessed by means of seedling emergence, life velocity index, shoot length and root length, total dry mass of seedlings and determination of water content, before and after each period of aging. The experimental design for the whole world was based on a 3 × 4 factorial scheme (three seed lots and four periods of 24, 48, 72 and 96 h duration), with separate evaluations at temperatures of 38 °C and 41 °C. The accelerated aging test conducted at a temperature of 41 °C for 24 h was a more suitable combination for separating batches of P. moniliformis according to different levels of vigour, and made it possible to obtain results similar to the classification of lots in relation to the initial quality.

scholarly journals Post-Processing Time Dependence of Shrinkage and Mechanical Properties of Injection-Molded Polypropylene

Materials ◽  
2020 ◽  
Vol 14 (1) ◽  
pp. 22
Author(s):  
Artur Kościuszko ◽  
Dawid Marciniak ◽  
Dariusz Sykutera
Keyword(s):  
Mechanical Properties ◽  
Impact Strength ◽  
Injection Molding ◽  
Accelerated Aging ◽  
Mold Temperature ◽  
Degree Of Crystallinity ◽  
Injection Mold ◽  
Secondary Crystallization ◽  
Scanning Calorimetry ◽  
Injection Molded

Dimensions of the injection-molded semi-crystalline materials (polymeric products) decrease with the time that elapses from their formation. The post-molding shrinkage is an effect of secondary crystallization; the increase in the degree of polymer crystallinity leads to an increase in stiffness and decrease in impact strength of the polymer material. The aim of this study was to assess the changes in the values of post-molding shrinkage of polypropylene produced by injection molding at two different temperatures of the mold (20 °C and 80 °C), and conditioned for 504 h at 23 °C. Subsequently, the samples were annealed for 24 h at 140 °C in order to conduct their accelerated aging. The results of shrinkage tests were related to the changes of mechanical properties that accompany the secondary crystallization. The degree of crystallinity of the conditioned samples was determined by means of density measurements and differential scanning calorimetry. It was found that the changes in the length of the moldings that took place after removal from the injection mold were accompanied by an increase of 20% in the modulus of elasticity, regardless of the conditions under which the samples were made. The differences in the shrinkage and mechanical properties of the samples resulting from mold temperature, as determined by tensile test, were removed by annealing. However, the samples made at two different injection mold temperature values still significantly differed in impact strength, the values of which were clearly higher for the annealed samples compared to the results determined for the samples immediately after the injection molding.

scholarly journals Genetic diversity for physiological quality of seeds from corn (Zea mays L.) intervarietal crossbreeds

2013 ◽  
Vol 35 (4) ◽  
pp. 449-456 ◽  
Author(s):  
Daniele Nerling ◽  
Cileide Maria Medeiros Coelho ◽  
Rubens Onofre Nodari
Keyword(s):  
Genetic Diversity ◽  
Zea Mays L ◽  
Accelerated Aging ◽  
Genetic Contribution ◽  
Percentage Germination ◽  
Canonical Variables ◽  
Accelerated Aging Test ◽  
Aging Test ◽  
Physiological Quality

The physiological quality is based on the genotype and may be accompanied since the first stages of selection through the study of genetic diversity. The purpose of this study was to evaluate the parental genetic contribution in the seed physiological quality in corn intervarietal crossbreeds. The intervarietal crossbreeds were performed using landraces genotypes, open pollinated varieties and commercial hybrids. The seeds obtained from the crossbreed, their equivalents and parentals were evaluated regarding their water percentage, germination, germination speed rate, accelerated aging, field emergence and electrical conductivity. The seeds obtained in the crossbreed are viable and vivid with heterosis when compared with the parentals. The accelerated aging test was more effective for selecting the strongest genotypes. The canonical variables were useful to group the genotypes that presented similar physiological characteristics. The genotypes MPA 01 x Pixurum 05, MPA 01 x AS1565, MPA 01 x SJC5886, SJC5886 x Pixurum 05 and Fundacep 35 x SCS 154 Fortuna were the best crossbreeds regarding the production of better physiological quality seeds.

scholarly journals Accelerated aging test in amaranth (Amaranthus cruentus L.) seeds

2018 ◽  
Vol 12 (03) ◽  
pp. 444-448
Author(s):  
Andréa Bicca Noguez Martins ◽  
◽  
Caroline Jácome Costa ◽  
Fernanda da Motta Xavier ◽  
André Pich Brunes ◽  
...  
Keyword(s):  
Accelerated Aging ◽  
Amaranthus Cruentus ◽  
Accelerated Aging Test ◽  
Aging Test

scholarly journals Effects of Injection Molding Screw Tips on Polymer Mixing

2018 ◽  
Vol 62 (3) ◽  
pp. 241-246 ◽  
Author(s):  
Dániel Török ◽  
József Gábor Kovács
Keyword(s):  
Injection Molding ◽  
Processing Parameters ◽  
Raw Material ◽  
Molding Machine ◽  
Surface Color ◽  
Melt Temperature ◽  
Injection Molding Machine ◽  
Aesthetic Appearance ◽  
Molded Parts ◽  
Injection Molded

In all fields of industry it is important to produce parts with good quality. Injection molded parts usually have to meet strict requirements technically and aesthetically. The aim of the measurements presented in our paper is to investigate the aesthetic appearance, such as surface color homogeneity, of injection molded parts. It depends on several factors, the raw material, the colorants, the injection molding machine and the processing parameters. In this project we investigated the effects of the injection molding machine on surface color homogeneity. We focused on injection molding screw tips and investigated five screw tips with different geometries. We produced flat specimens colored with a masterbatch and investigated color homogeneity. To evaluate the color homogeneity of the specimens, we used digital image analysis software developed by us. After that we measured the plastication rate and the melt temperature of the polymer melt because mixing depends on these factors. Our results showed that the screw tips (dynamic mixers) can improve surface color homogeneity but they cause an increase in melt temperature and a decrease in the plastication rate.

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