Processing Temperatures Influence of Three Types …

1 MATERIALE PLASTICE 52 No. 1 2015 Temperatures Influence ofThree Types of Polyamide reinforced with DifferentPercentages of Fiber Glass on Some Mechanical PropertiesGHEORGHE RADU EMIL MARIES*University of Oradea, 1 Universit ii Str., 410087, Oradea, Rom niaThis paper analyses the Influence of Processing Temperatures of polyamide Grivory type HTV-3H1 noir9205, polyamide Grivory type HTV-45H1 noir 9205 and polyamide Grivory type HTV-6H1 noir 9205 onsome mechanical properties, when injecting items used in various technical articles. The test-specimens onPA Grivory type HTV-3H1 noir 9205 were molded at the following injection Temperatures : 310, 320, 330,340 and 350 C. The test-specimens on PA Grivory type HTV-45H1 noir 9205 were molded at the followinginjection Temperatures : 320, 330, 340, 350 and 360 C.

2 The test-specimens on PA Grivory type HTV-6H1noir 9205 were molded at the following injection Temperatures : 330, 340, 350, 360 and 370 C. These specimenswere tested using methods for determination of the following mechanical properties: tensile strength, Izodimpact strength and hardness (Shore). For all these polymers, it was determined that increasing of injectiontemperature results in insignificant changes of hardness. The Izod impact strength decreases with increasingthe injection temperature. After reaching the minimum value, Izod impact strength increases again if theprocessing temperature is raised further. The tensile strength at break increases with increasing the processingtemperature. After reaching the maximum value, tensile strength at break decreases if the processingtemperature is raised : polyamide (PA ), tensile tests, Izod impact test, Shore Durometer hardness test.

3 Polyethylenes (PE), polyamides (PA), thermoplasticpolyurethanes (TPU), polyoxymethylenes (POM),polypropylene (PP), polymethyl methacrylate (PMMA),cellulose acetate (CA), polyvinyl chloride (PVC),polystyrene (PS) and its derivatives, etc may be mentionedamongst the most frequently used polymers formanufacturing of technical parts in various industries. Themost frequently used Processing technology for thesepolymers is have good dimensional stability, high rigidity(especially when PA is reinforced with fibre glass), goodresistance to compression, wear, shocks and vibrations;they are hard materials, and maintain their hardness andtenacity at high Temperatures , with no visibletransformations up to 80-90 C [1,2].

4 PAs are semi-transparent in molded parts with thin wall and opaque inmolded parts with thick wall. Reinforcing polyamides withfiber glass results in improved properties of tensile strength,bending resistance and higher values for elastic modulusand hardness. Applications: mechanical engineering(friction parts, tooth wheels, wheel bands), automotiveparts (motor housings, fans, parts with sofisticated forms,fuel tanks, bushings, flexible cabling, brake fluid reservoirs),electrical and electronics parts, household items (fruitjuicers, kitchen robots, handles of tableware), sport andtourism equipment (ski boots, roller skates, tents, climbingropes and cords, protective helmets, anti-drop system forbicycle chain), footware (shoe soles) [3].

5 At injection molding of polymeric materials, thecharacteristics of molded products are highly influencedby the polymer temperature, mold temperature, coolingtime and the pressure of the flowing state material duringfilling the mold cavity [4 - 8,13].The present paper aims to analyze the variation of somemechanical properties with injection processingtemperature through methods for determination of tensilestrength at break, Izod impact strength and penetrationhardness (Shore D hardness) for PA Grivory noir 9205,type HTV-3H1, HTV-45H1 and HTV-6H1, polymers used atmolding technical products in various partThe test-specimens were injection molded on thefollowing materials: polyamide Grivory type HTV-3H1noir 9205 (PA + 30% fiber glass), polyamide Grivorytype HTV-45H1 noir 9205 (PA + 45% fiber glass) andpolyamide Grivory type HTV-6H1 noir 9205 (PA +60% fiber glass), using a machine ENGEL CC 100, type ES80/50 HL, year of manufacturing 1995 ( ).

6 The temperature of the flowing state material wasmeasured using thermocouples placed on theplastification-injection cylinder. The test-specimens on Grivory type HTV-3H1 noir 9205 were molded at thefollowing injection Temperatures : 310, 320, 330, 340 and350 C. The test-specimens on PA Grivory type HTV-45H1 noir 9205 were molded at the following injection* email: Tel.: Injection moldingmachine ENGEL CC 100 TypeES 80/50 HLMATERIALE PLASTICE 52 No. 1 2015 : 320, 330, 340, 350 and 360 C. The test-specimens on PA Grivory type HTV-6H1 noir 9205 weremolded at the following injection Temperatures : 330, 340,350, 360 and 370 C. The injection molded test-specimensare shaped according to figure the injection molding of the test-specimens onPA Grivory noir 9205, type HTV-3H1,, HTV-45H1 andHTV-6H1, the parameters that Influence the injectioncycles were maintained constant excepting the the test-specimens made by injection molding weretested in order to determine the following mechanicalproperties: Shore D hardness, Izod impact strength andtensile strength at of the Shore D hardnessThe Shore D hardness was determined with a durometertype D, model SAUTER HB/Germany ( ).

7 The methodconsisted in measuring the initial penetration (depth) ontest-specimen and instant recording (less than 1s frompressing) of the values indicated by the to the user manual, the pendulum arm at theinitial angle of 150 has an initial potential energy of 7,5 Izod impact strength of unnotched specimens (aiU)according to SR EN ISO 180 is calculated using thefollowing equation: (1)whereEc - energy (in J) absorbed at breaking the specimenh - specimen thickness (in mm)b specimen width (in mm)The software of the PENDOLO P400 device displaysautomatically the value of the energy absorbed at breakingthe test-specimen. The test-specimens were fixed inparallel mode. A batch of ten (10) samples was molded ateach Processing setting and then was tested in order todetermine a final result as arithmetic mean of the of the tensile strength at breakDetermination of the tensile strength at break was madeusing a tensile testing machine WPM VEB ThuringerIndustrie werk, Ranenstein gerat R 37, Typ 2092 ( ).

8 Tests were carried out in accordance with the EuropeanStandard SR EN ISO 527-1:2000 [11] and SR EN ISO 527-2:2000 [12] on test-specimens with forms and dimensionssuch as those illustrated in figure 8. The testing speed for all samples was 200 mm/min. Abatch of ten (10) samples was molded at each processingsetting and then was tested in order to determine a finalresult as arithmetic mean of the measured tensile strength at break was calculated using thefollowing equation: (2)whereF - force [N] measured at breaking the specimenA initial cross-sectional area [mm2] of the test-specimenFig. 2 Polyamide test-specimens made byinjection Shore D durometer,model SAUTER HB/GermanyThe tests were carried out in accordance with theEuropean Standard SR EN ISO 868:2003 [9] on test-specimens with forms and dimensions such as thoseillustrated in figure 4.

9 A batch of twenty-five (25) sampleswas molded at each Processing setting and then was testedin order to determine a final result as the arithmetic meanof the measured Test-specimen for thehardness determinationMeasurement of the Izod impact strengthThe Izod impact test was performed on unnotchedspecimens ( ).The tests were carried out in accordance with theEuropean Standard SR EN ISO 180 [10] using a pendulumimpact tester model PENDOLO P400, manufactured byHAMMEL/ England ( ) Test-specimen forthe Izod Izod impact tester,model PENDOLO P400,HAMMEL/ Tensile testing machine,WPM VEB ThuringerIndustrie werk, Ranensteingreat R 37, Typ Test-specimen for tensile strength determinationMATERIALE PLASTICE 52 No.

10 1 2015 and discussionsThe test-specimens on PA Grivory noir 9205, typesHTV-3H1, HTV-45H1 and HTV-6H1 were tested using adurometer type D in order to determine the penetrationhardness (table 1).It can be noted that increasing the processingtemperature of PA Grivory, type HTV-3H1 noir 9205 from310 to 330 C results in a slightly increased hardness. Themaximum hardness was N/mm2 measured at330 C. The further raise in Processing temperature resultsin a decrease of hardness at in Processing temperature of PA Grivory,type HTV-45H1 noir 9205 from 320 to 340 C results in aslightly increase of hardness. The maximum hardness N/mm2 measured at 340 C. The further raise inprocessing temperature results in a decrease of hardnessat the Processing temperature of PA Grivory,type HTV-6H1 noir 9205 from 330 to 350 C results in aslightly increase of hardness.