graphical reprentation of elasticity and damping as a function of temperature or frequency.
5.2This procedure can be ud to locate transition tempera-tures of plastics,that is,changes in the molecular motions of a polymer.In the temperature ranges where significant changes occur,elastic modulus decreas rapidly with increasing tem-perature(at constant or near constant frequency)or increas with increasing frequency(at constant temperature).A maxi-mum is obrved for the loss modulus.
5.3This procedure can be ud,for example,to evaluate by comparison to known reference materials:
5.3.1Degree of pha paration in multicomponent sys-tems,
5.3.2Filler type,amount,pretreatment,and dispersion,and 5.3.3Effects of certain processing treatment.
5.4This procedure can be ud to determine the following: 5.4.1Stiffness of polymer composites,especially as a func-tion of temperature,
5.4.2Degree of polymer crystallinity,and
5.4.3Magnitude of triaxial stress state in the rubber pha of rubber modified polymers.
5.4.4This procedure is uful for quality control,specifica-tion acceptance,and rearch.
5.5For many materials,there may be a specification that requires the u of this practice,but with some procedural modifications that take precedence when adhering to the specification.Therefore,it is advisable to refer to that material specification before using this practice.Table1of Classifica-tion System D4000lists the ASTM materials standards that currently exist.
6.Interferences
6.1Since small quantities of specimen are ud,it is esntial that the specimens be homogeneous or reprentative, or both.
7.Apparatus
7.1The function of the apparatus is to hold a plastic specimen of uniform cross ction,so that the specimen acts as the elastic and dissipative element in a mechanically oscillated system.Instruments of this type are commonly called dynamic mechanical or dynamic thermomechanical analyzers.They typically operate in one of ven oscillatory modes:(1)freely decaying torsional oscillation,(2)forced constant amplitude, resonant,flexural oscillation,(3)forced constant amplitude,fixed frequency,compressive oscillation,(4)forced constant amplitude,fixed frequency,flexural oscillation,(5)forced, constant amplitude,fixed frequency,tensile oscillation,(6) forced constant amplitude,fixed frequency,torsional oscilla-tion and(7)forced constant amplitude,fixed frequency,or variable frequency dual cantilever.
7.2The apparatus shall consist of the following:
7.2.1Clamps—A clamping arrangement that permits grip-ping of the sample.
7.2.2Oscillatory Deformation(Strain)—A device for ap-plying an oscillatory deformation(strain)to the specimen.The deformation(strain)may be applied and then relead,as in free-vibration devices,or continuously applied,as in forced-vibration devices(e Table1).
7.2.3Detectors—A device or devices for determining de-pendent and independent experimental para
meters,such as force(stress or strain),frequency,and temperature.Tempera-ture should be measureable with an accuracy of61°C, frequency to61%,and force to61%.
7.2.4Temperature Controller and Oven—A device for con-trolling the specimen temperature,either by heating(in steps or ramps),cooling(in steps or ramps),or maintaining a constant specimen environment.Any temperature programmer should be sufficiently stable to permit measurement of sample tem-perature to60.5°C.
7.3Nitrogen or other gas supply for purging purpos. 7.4Calipers or other length-measuring device capable of measuring to an accuracy of0.01mm.
8.Hazards
8.1Precautions:
8.1.1Toxic or corrosive effluents,or both,may be relead when heating the specimen near its decomposition point and can be harmful to personnel or to the apparatus.
8.1.2Take care to prevent buckling of the clamped speci-men due to thermal expansion during the test.
9.Test Specimens
9.1Specimens may be any uniform size or shape but are ordinarily analyzed in rectangular form.If some heat treatment is applied to the specimen to obtain this preferred analytical form,this treatment should be noted in the report.
9.2Due to the numerous
types of dynamic mechanical instruments,specimen size is notfixed by this practice.In many cas,a specimen of0.75by9.4by50mm(0.03by0.38 by2.0in.)is found to be usable and convenient.
N OTE3—It is important to lect a specimen size consistent with the modulus of the material under test and capabilities of the measuring apparatus.For example,thick specimens of low modulus materials may be suitable for measurement,while thin specimens of high modulus materials may be required.
9.3Condition the specimen at2362°C(7364°F)and50 65%relative humidity for not less than40h prior t
o test in accordance to Procedure A of Practice D618,for tho tests where conditioning is required.If other specimen conditioning is ud,it should be noted in the report.
10.Calibration
new bird10.1Using the same heating rate or schedule to be ud for specimens,calibrate the instrument temperature axis,using the instrument manufacturer’s procedures with either or both of the following substances.
Standard Transition Temperature,°C Type of Transition
Water0.0fusion打电话技巧
Indium156.6fusion
10.2Calibrate the instrument using procedures recom-mended by the manufacturer.
11.Procedure
11.1Measure the length,width,and thickness of the speci-men to an accuracy of61%.
11.2Maximum strain amplitude should be within the linear viscoelastic range of the material.Strains of less than1%are recommended.
11.3If temperature is to be the independent variable:
11.3.1The test frequency may be from0.01to500Hz,fixed
or changing as the dependent variable.
TABLE1Summary of Techniques and Calculations Ud to Determine Dynamic Mechanical Properties
Sinusoidal fixed frequency Forced constant fixed frequency-tensile oscillation (e Fig.4)
Sinusoidal fixed or Forced constant amplitude;
fixed or variable
0.0016
variable frequency
frequency-tensile oscillation(e Fig.5) Forced constant amplitude;fixed or variable frequency-compressive oscillation(e Fig.6)
Forced constant amplitude;fixed or variable frequency-flexural oscillation(e Fig.7)batch是什么意思
Technique
Input
Excitation
Mode of Oscillation
Frequency Range,
Hz
Specimen Size,
yrll是什么意思mm
Calculations
Oscillating
Strain
Elastic
Component
Damping
Component
r=0.25–3.2
L=63.5
3ra/L2Circular crosstrina
blogerction:
E8=4NL3
cos d/3r4a
E9=4NL3sin d/
3r4a
Tan d directly read
Dynamic Mechanical Sinusoidal
fixed or
Constant force
amplitude;
0.01–50t=up to2.0
b=up to10
D L/L Rectangular cross
ction:
Analyzer B,D variable
frequency fixed or variable
frequency-tensile
L=up to24E8=NL cos d/bt
D/L
E9=NL sin d/
tb D L
oscillation(e Fig.5)Tan d directly
read
r=up to2.0
L=up to24
D L/L Circular cross
ction:
E8=NL cos d/p r2
D/Lreduces
E9=NL sin d/p r2
D/L
Tan d directly read
Dynamic Sinusoidal Constant force amplitude;0.01–50Up to3320D L/L Rectangular cross
Mechanicalfixed orfixed or variable t=up to20ction:
Analyzer B,D variable frequency-compression b=up to20E8=NL cos d/tb E9=NL sin d/ frequency oscillation(e Fig.6)L=0.001-24D L tb D L
r=1–20Tan d directly
read
t=up to20
D L/L Circular cross
ction:
E8=NL cos d/p r2 D L E9=NL cos d/
p r2D L
Tan d directly read
Dynamic Mechanical Analyzer B,D Sinusoidal
fixed or
variable
frequency
Constant force amplitude;
fixed or variable
frequency-flexural
oscillation(e Fig.7)
0.01–50t=up to24
b=up to10
L=up to20
3ta/L2
E8
2
r=up to5
L=up to20
3ra/L2
E8
Mechanical spectrometer B,C Sinusoidal
fixed or
variable
frequency
Forced constant amplitude;
fixed or variable
frequency-torsional
oscillation(e Fig.8)
0.0016–800.5to6.4t12.7b
63.5L
Rectangular
cross
ction:
K u
(3a+1.8b)/
8b2L t2
G8
K
Tan d directly read
3.2,
4.7,6.4dia,
63.5L
Circular
cross
ction:
Circular cross
ction:
Technique
Input
Excitation
Mode of Oscillation
Frequency Range,
Hz
Specimen Size,
mm
Calculations
Oscillating
Strain
Elastic
Component
Damping
Component
r u/L G8=2TL cos d/p r4u G9=2TL sin d/p r4u
Tan d directly read
Mechanical spectrometer B,C Sinusoidal
fixed
frequency
Forced constant amplitude
fixed frequencyflexural
oscillation(single or dual
cantilever)
.01–200L=1–46
t=.1–5
b=.1–18
3ta/L2
E85
S810D
2b~t/L!3
Tan d directly read
Mechanical spectrometer B,C Sinusoidal
fixed
frequency
Forced constant amplitude
fixed frequency shear
oscillation
.01–200t=.1–3a/t
G85
S810D t
2A
regard是什么意思Tan d directly read
Mechanical spectrometer B,C Sinusoidal
fixed
frequency
Forced constant amplitude
fixed frequency tensile
oscillation
.01–100t=.005–1
b=.01–18
L=1–20
existencea/L
E85
S810D L
traffic是什么职业
wt
Tan d directly read
available from IMASS,Inc.,Box
available from TA Instruments,
available from Rheometric-Scientific,
available from The Perkin-Elmer
inertial member
clamp
D L=change in length n=number of cycles for oscillation to decay a specific amount E8=elastic modulus P=period of oscillation
E9=loss modulus d=pha angle
N=axial force
Z=elapd time
R=instrument arm length
