Thermal and Mechanical Analysis.ppt

1、Thermal and Mechanical Analysis,CNMR Athlone Institute of Technology,Alan Murphy,Introduction,Plastic materials are tested throughout their life:Monomer / Reactants Polymer / Raw Material & Additives Product / Design Product / Research & Development Processing / Quality Control Product / Service Pro

2、duct / End of Life,CNMR Athlone Institute of Technology,Introduction,A knowledge of available test methods is useful to:Identify Research & Development requirements Control incoming raw material quality Quantify product specifications Understand material data sheets Correct manufacturing problems In

3、vestigate customer complaints Continuously improve the product,CNMR Athlone Institute of Technology,Introduction,Raw Material TestingControl of raw material helps to assure consistent processing and end product characteristics.Melt Flow Rate and Density are the most common raw material tests but oth

4、er raw material tests may be specified if warranted by the product.Eg.1 Impact test for safety glasses.Eg.2 GPC for molecular weight controlEg 3. TGA to measure % glass content,CNMR Athlone Institute of Technology,Introduction,Testing during processingQC tests, such as weight or moisture content Tro

5、ubleshooting tests, such as investigating :Why a component is cracking during assembly Why an extruded tube is shrinking after manufacture Where contamination is coming from & what type,CNMR Athlone Institute of Technology,Introduction,Testing during serviceResearch and Development tests, such as co

6、mparison of alternative materials or property loss with time.Customer complaints.eg Why has the product failed after 3 months use ?Why has the product embrittled ?Why has discolouration occurred ?,CNMR Athlone Institute of Technology,Thermal Analysis,ANALYTICAL TECHNIQUESDifferential Scanning Calori

7、metry (DSC)Dynamic Mechanical Thermal Analysis (DMTA)Thermogravimetric Analysis (TGA)Melt Flow Rheology (MFI)Gel Permeation Chromatography (GPC),CNMR Athlone Institute of Technology,Thermal Analysis,Differential Scanning Calorimetry (DSC),DSC is a thermal method of analysis to study the thermal beha

8、viour and thermal properties of materials (typically polymers). The material is sealed in a sample pan and subjected to a controlled temperature programme.The resulting thermograph can yield much valuable information about the properties of the material analysed.,Main use of DSC: Material Identifica

9、tion (Tm and DHf) based on IS EN ISO 3146:2000; Method C2,CNMR Athlone Institute of Technology,Thermal Analysis,Differential Scanning Calorimetry (DSC),CNMR Athlone Institute of Technology,Thermal Analysis,Differential Scanning Calorimetry (DSC),Other uses of DSC: % Crystallinity determination by DS

10、C (based on IS EN ISO 3146:2000; Method C2).Purity and Polymorphism analysis by DSC.Thermal Stability of materials (e.g. oxidative induction time (OiT) of materials) by DSC.,CNMR Athlone Institute of Technology,Thermal Analysis,Differential Scanning Calorimetry (DSC),CNMR Athlone Institute of Techno

11、logy,Thermal Analysis,Dynamic Mechanical Thermal Analysis (DMTA),CNMR Athlone Institute of Technology,Dynamic Mechanical Thermal Analysis (DMTA) records the temperature-dependent visco-elastic properties and determines the modulus of elasticity and the damping values by applying an oscillating force

12、 to the sample.Thermal method of analysis used to determine thermo-mechanical properties of materials (i.e. Glass Transition Temperature Tg). Used as an alternative to DSC which is typically estimating Tg.Used to more accurately determine the Tg value, strength and temperature-dependant elongation o

13、f a material. in several modes,Thermal Analysis,Thermogravimetric Analysis (TGA),TGA measures the weight of a substance heated at a controlled rate as a function of temperature or time.All materials ultimately decompose on heating, and the decomposition temperature and profile is a characteristic pr

14、operty of each material.,Main use of TGA: Inorganic Content of Material,CNMR Athlone Institute of Technology,Thermal Analysis,CNMR Athlone Institute of Technology,Thermal Analysis,Thermogravimetric Analysis (TGA),Other uses of TGA:Material Thermal Stability.Moisture and Volatiles Content (TG-IR).Com

15、position of Multi-Component Systems.Shelf-Life Studies and Decomposition Kinetics.,CNMR Athlone Institute of Technology,Thermal Analysis,Thermogravimetric Analysis (TGA),CNMR Athlone Institute of Technology,% Polymer = 64.4%,% Carbon Black = 3.4%,% Glass Fibre = 32.2%,Rheological Analysis,Melt Flow

16、Rate (MFR) to ISO 1133.Grams of material that flow through a simple die in 10 minutes using a loaded piston and a set temperature.Is a measure of Shear Viscosity and is directly proportional to the average molecular weight.Uses: Raw material control; processing quality; regrind studies; useful troub

17、leshooting test,CNMR Athlone Institute of Technology,CNMR Athlone Institute of Technology Rheological Analysis,Capillary Rheometry: uses motor driven pistons to produce high pressures and two barrels with dies to measure shear viscosity and elongational viscosity.Mimics processing conditions; gives

18、information on average molecular weight and molecular weight distribution.Uses: mould and die design; new material validation; troubleshooting; raw material control,CNMR Athlone Institute of Technology Mechanical Analysis,Tensile Testing to ISO 527Measures the strength of a material and its flexibil

19、ity (elongation).Also used to measure peel strength, bond strength, weld strength.Carried out on dumbbell specimens or actual product.Uses: QC control for material or product,CNMR Athlone Institute of Technology Impact Analysis,Izod and Charpy Impact Testing to ISO 179/180.These are pendulum impact

20、tests generally done on test bars but can be adapted for small products.Usually notched, testing can be done at ambient or sub-zero temperatures. Uses: QC test, material comparison, notch sensitivity,CNMR Athlone Institute of Technology Aging Studies,Use of elevated temperatures to accelerate the ag

21、ing process of plastic products.Based on a 10C rise in environmental temperature produces a twofold increase in the degradation rate.Humidity can be applied too if considered a factor.Uses: shelf-life studies; product data; regrind analysis and the affect of other influences on product lifespan,Chem

22、ical Analysis,Gel Permeation Chromatography (GPC),GPC causes separation by various pore sizes in the column packing material, separating on the basis of molecular size, not molecular weight.Main use of GPC (or SEC): Measuring average molecular weight (Mp) and molecular weight distribution (Mw) of a

23、material.Typical Detection methods used are UV-vis and Refractive Index.,CNMR Athlone Institute of Technology,Chemical Analysis,Gel Permeation Chromatography (GPC),CNMR Athlone Institute of Technology,Case Study A,Contamination Issue:,The client sent one sample of their product with particulate on t

24、he bottom of the container.,How was it resolved?,FTIR and DSC were applied to determine the material types,CNMR Athlone Institute of Technology,Specimens were isolated and cleaned in Class 100 Cabinet,Case Study A,Contamination Issue:,CNMR Athlone Institute of Technology,Isolated White Particulate M

25、atter: FTIR Polytetrafluoroethylene (PTFE),Case Study A,Contamination Issue:,CNMR Athlone Institute of Technology,Isolated White Particulate Matter: DSC Tm = 329oC,Case Study A,Outcome:,CNMR Athlone Institute of Technology,The client checked their materials list and equipment associated with this pr

26、oduct.,The PTFE Source was determined to have come from a stirring bar used during manufacture of the solution.,Case Study B,CNMR Athlone Institute of Technology,A batch of parts were cracking in service after normal pressure was put on the end of the part.,Processing Issue:,How was it resolved?,GPC

27、 was used to compare both good and bad samples.,Case Study B,CNMR Athlone Institute of Technology,Therefore we looked at the process and decided to look at the moisture content of the pre-processed material:,Processing Issue:,Using Karl Fischer Coulometry we determined that the material had not been

28、 dried sufficiently.,This then led to the materials molecular weight being affected during processing causing the material in the part to be weakened.,Case Study C,CNMR Athlone Institute of Technology,A manufacturer using regrind polyethylene material experienced difficulties with contamination of s

29、creen plates within an extruder.The problem was thought to be caused by contamination of the regrind feedstock. CNMR were requested to:(1) Identify the contaminant;(2) Determine the source of contamination if possible;,Recycling Issue:,Case Study C,CNMR Athlone Institute of Technology,Debris from th

30、e screen plates was examined under an optical microscope. It was determined that the contamination was not compatible with the matrix and could be removed easily.,Recycling Issue:,FTIR determined that the materials present were PET-based.,PET,Case Study C,CNMR Athlone Institute of Technology,DSC con

31、firmed that the contamination had a Tm at ca. 250oC. This is typical of the melting characteristics demonstrated by PET.,Recycling Issue:,Material from two silos were analysed. The granules were separated simply according to density.Only one material from one of the silos was found to contain dense

32、particles.These particles had the same thermal characteristics as the contaminant.,THANK YOU.,CNMR Athlone Institute of Technology,CNMR Athlone Institute of Technology,Contact Details Mr. Mark Atterbury Mr. Alan Murphy Senior Research Officer Senior Research Officer Tel: 00353 9064 83070 00353 9064 42575 Email: matterburyait.ie amurphyait.ie,