Work Item
ASTM WK51072

Revision of D7028-07e1 Standard Test Method for Glass Transition Temperature (DMA Tg) of Polymer Matrix Composites by Dynamic Mechanical Analysis (DMA)

Keywords

None Provided

Rationale

This Work Item was created to address all negative comments on D30 (15-01) Ballot. The negatives were withdrawn so the standard could move forward and be approved for publishing. Page 5 - Please change the torque units for the clamps from 90-113 cNm to 0.9 - 1.1 Nm Page 12 - The test results shall be plotted in a diagram according to figures 1 and 2 showing storage modulus (log), loss modulus and tan delta versus temperature. (Johnnie McCord) This method has been brought up for ballot before, and has a negative that has not been cleared regarding calibration. The section refers to a method that major equipment manufacturers and calibration companies are not familiar with. The language restricts users that do not perform in-house calibrations of their equipment. I recommend removing the following sentence from section 9.1 The equipment must be calibrated in the same loading mode as will be used for testing, either dual cantilever or three-point bending. (Kevin Schuman) I already voted on this once and stated my concerns below. My comments were: I believe the method should use the standard boiler plate conditioning statement as used in other composites test methods. The majority of customers typically want their samples tested unconditioned as opposed to waiting for conditioning to dry or wet equilibrium. Currently, the method gives no wiggle room for conditioning; it has to be dry or wet conditioned per ASTM D5229. The scope of the method should remove the wording stating determination of dry or wet glass transtion temperature and give the flexibility to simply test for Tg of composite materials under any specified conditioning ( unconditioned for example).Regarding Calibration under Section 9.1: It should be confirmed that ASTM E1867 is actually being followed by laboratories and calibration companies. After a recent purchase of DMA instrument, the equipment manufacturer and a calibration service stated they had never heard of calibrating using ASTM E1867 and are not familiar with other labs employing this technique. If ASTM E1867 is not being utilized in the industry, it should be removed and replaced with what the industry is doing. It is understood that there are many variables that affect Tg in a DMA test such as temperature ramp rate, purge gas, purge gas flow rate, mode of oscillation, thermocouple placement, etc.. Part of my concern is that being an accredited laboratory, we cannot perform calibration of equipment. We can do verifications, but under our scope of accreditation we are not allowed to actually calibrate a piece of equipment. That means if we have our instrument calibrated at a certain heating rate, we cannot use it for other heating rates. Various DMA methods call out 1, 2, 3, 5C/min. The method is asking for an unrealistic approach and is nearly impossible to adhere to the equirements unless you limit the DMA to using one mode of oscillation and one heating rate, or we go outside our of scope of accreditation and make changes to the settings made by the calibration house. (Glenn A Sime)

Details

Developed by Subcommittee: D30.04

Committee: D30

Staff Manager: Melissa Marcinowski

Work Item Status

Date Initiated: 07-29-2015

Technical Contact: Mike Stuart

Item: 001

Ballot: D30.04 (16-01)

Status: Will Reballot Item

Item: 001

Ballot: D30 (17-01)

Status: Will Reballot Item

Item: 006

Ballot: D30 (18-01)

Status: Negative Votes Need Resolution