JEC COMPOSITES MAGAZINE - Issue #107 - August/September 2016 - 60

TECHNOLOGY reaction kinetics

Fig. 3: Temperature
progression during
cure of the XB3585/
XB3458 epoxy resin
[3]

Fig. 4: Comparison
of the maximum
heat flow of the
epoxy systems
under isothermal
conditions [5]

Fig. 1: Part of
a convertible roof
cover manufactured
with a toughened,
fast-cure resin

Cure kinetics of fast-cure epoxy
As the epoxy cure reaction is exothermic, the resin temperature can
overshoot the mould temperature. When manufacturing a composite
plate in a mould, the magnitude of the overshoot depends on the mass
of resin and the plate thickness. The heat flow in the resin is limited by
the low thermal conductivity (0.2 W/(m °C)) of the epoxy, meaning
that heat will not readily dissipate once produced.
The exothermic reaction during cure can be characterised by measuring the heat flow using differential scanning calorimetry (DSC).
The severity of the exothermic reaction depends on the total heat of
reaction (integral of the heat flow curve) and the time span in which
the heat is released. Isothermal DSC measurements of the XB3585/
XB3458 and RTM6 systems are shown in Fig. 2. Two important
differences between these two epoxies explain why the XB3585/
XB3458 system has a much higher tendency to overshoot the mould
temperature than RTM6:
i) The total heat of reaction derived from dynamic DSC measurements is in the same order of magnitude for both materials with a
slightly higher value of 494 ±4 J/g for the fast-cure resin and 457 J/g
for RTM6 [4]. However, the release of a similar amount of energy
within a much shorter time span results in a higher heat flow. The heat

Fig. 2: Isothermal DSC
measurements of the
XB3585/XB3458 system
compared to RTM6 epoxy
resin

60

flow of the XB3585/XB3458 system at 100°C is a factor of 20 higher
than RTM6 at 180°C, their respective recommended processing temperatures.
ii) The heat flow of the XB3585/XB3458 system peaks very early in
the cure process, indicating that a large amount of heat is released at
cure reaction initiation. In contrast, a slow, steady increase of the heat
flow can be measured with RTM6.
A temperature progression measured during cure is shown in Fig. 3
for a 3-mm-thick bulk epoxy plate manufactured using an aluminium
mould at 100°C. The temperature increased from 100°C to 176°C
within 20 seconds. Typically, the temperature distribution during
such a strong overshoot is not homogeneous but rather shows a significant variation with the maximum temperature in the centre of the
mould, and only a small overshoot close to the mould surface. These
phenomena affect the part during processing and can result in defects
of the final part such as material decomposition or internal stress.

Influence of silica nanoparticles
Dynamic and isothermal DSC measurements were conducted and
the maximum heat flow was extracted, as shown in Fig. 4. The heat
flow was found to be inversely proportional to the wt.% of silica nanoparticles. The glass transition temperature, Tg, remained unaffected
with a constant value of 121 ±1°C. These results indicate that the particles do not influence the cure reaction adversely, but do reduce the
exothermic mass.
The temperature overshoot was reduced from 176°C for the unmodified epoxy to 166°C and 157°C with the addition of 10 wt.% and 20
wt.% of silica nanoparticles respectively. The importance of this temperature reduction for the modelled case can be shown by comparing

jec composites magazine / No107 August - September 2016



Table of Contents for the Digital Edition of JEC COMPOSITES MAGAZINE - Issue #107 - August/September 2016

Cover
Edito
OPINION
internet of things
Contents
NEWS
In Brief
Agenda
JEC Conferences 2017
EXPERIENCE COMPOSITES
Innovations
Interview
CCEV
Symposium
BUSINESS
Outlook
Automotive
MANUFACTURING
Injection
Hybrid Structures
Robotics
Total production optimization
Company visit
FEATURED TRANSPORTATION : What share for composites in transportation?
Biocomposites
Railway
Design
Tanks
Truck
Public transportation
SOLUTIONS
Construction
Parasports
Sailing
Watersports
In the world
TECHNOLOGY
Reaction kinetics
Index
Software
Advertisers
JEC COMPOSITES MAGAZINE - Issue #107 - August/September 2016 - Back Cover
JEC COMPOSITES MAGAZINE - Issue #107 - August/September 2016 - Cover
JEC COMPOSITES MAGAZINE - Issue #107 - August/September 2016 - 2
JEC COMPOSITES MAGAZINE - Issue #107 - August/September 2016 - Edito
JEC COMPOSITES MAGAZINE - Issue #107 - August/September 2016 - NEWS
JEC COMPOSITES MAGAZINE - Issue #107 - August/September 2016 - 5
JEC COMPOSITES MAGAZINE - Issue #107 - August/September 2016 - Contents
JEC COMPOSITES MAGAZINE - Issue #107 - August/September 2016 - 7
JEC COMPOSITES MAGAZINE - Issue #107 - August/September 2016 - In Brief
JEC COMPOSITES MAGAZINE - Issue #107 - August/September 2016 - 9
JEC COMPOSITES MAGAZINE - Issue #107 - August/September 2016 - Agenda
JEC COMPOSITES MAGAZINE - Issue #107 - August/September 2016 - JEC Conferences 2017
JEC COMPOSITES MAGAZINE - Issue #107 - August/September 2016 - Innovations
JEC COMPOSITES MAGAZINE - Issue #107 - August/September 2016 - 13
JEC COMPOSITES MAGAZINE - Issue #107 - August/September 2016 - 14
JEC COMPOSITES MAGAZINE - Issue #107 - August/September 2016 - Interview
JEC COMPOSITES MAGAZINE - Issue #107 - August/September 2016 - 16
JEC COMPOSITES MAGAZINE - Issue #107 - August/September 2016 - CCEV
JEC COMPOSITES MAGAZINE - Issue #107 - August/September 2016 - Symposium
JEC COMPOSITES MAGAZINE - Issue #107 - August/September 2016 - 19
JEC COMPOSITES MAGAZINE - Issue #107 - August/September 2016 - 20
JEC COMPOSITES MAGAZINE - Issue #107 - August/September 2016 - Outlook
JEC COMPOSITES MAGAZINE - Issue #107 - August/September 2016 - 22
JEC COMPOSITES MAGAZINE - Issue #107 - August/September 2016 - 23
JEC COMPOSITES MAGAZINE - Issue #107 - August/September 2016 - Automotive
JEC COMPOSITES MAGAZINE - Issue #107 - August/September 2016 - 25
JEC COMPOSITES MAGAZINE - Issue #107 - August/September 2016 - Injection
JEC COMPOSITES MAGAZINE - Issue #107 - August/September 2016 - 27
JEC COMPOSITES MAGAZINE - Issue #107 - August/September 2016 - Hybrid Structures
JEC COMPOSITES MAGAZINE - Issue #107 - August/September 2016 - 29
JEC COMPOSITES MAGAZINE - Issue #107 - August/September 2016 - 30
JEC COMPOSITES MAGAZINE - Issue #107 - August/September 2016 - 31
JEC COMPOSITES MAGAZINE - Issue #107 - August/September 2016 - Robotics
JEC COMPOSITES MAGAZINE - Issue #107 - August/September 2016 - 33
JEC COMPOSITES MAGAZINE - Issue #107 - August/September 2016 - Total production optimization
JEC COMPOSITES MAGAZINE - Issue #107 - August/September 2016 - 35
JEC COMPOSITES MAGAZINE - Issue #107 - August/September 2016 - Company visit
JEC COMPOSITES MAGAZINE - Issue #107 - August/September 2016 - 37
JEC COMPOSITES MAGAZINE - Issue #107 - August/September 2016 - Biocomposites
JEC COMPOSITES MAGAZINE - Issue #107 - August/September 2016 - 39
JEC COMPOSITES MAGAZINE - Issue #107 - August/September 2016 - 40
JEC COMPOSITES MAGAZINE - Issue #107 - August/September 2016 - Railway
JEC COMPOSITES MAGAZINE - Issue #107 - August/September 2016 - 42
JEC COMPOSITES MAGAZINE - Issue #107 - August/September 2016 - Design
JEC COMPOSITES MAGAZINE - Issue #107 - August/September 2016 - 44
JEC COMPOSITES MAGAZINE - Issue #107 - August/September 2016 - 45
JEC COMPOSITES MAGAZINE - Issue #107 - August/September 2016 - 46
JEC COMPOSITES MAGAZINE - Issue #107 - August/September 2016 - 47
JEC COMPOSITES MAGAZINE - Issue #107 - August/September 2016 - Truck
JEC COMPOSITES MAGAZINE - Issue #107 - August/September 2016 - 49
JEC COMPOSITES MAGAZINE - Issue #107 - August/September 2016 - Public transportation
JEC COMPOSITES MAGAZINE - Issue #107 - August/September 2016 - 51
JEC COMPOSITES MAGAZINE - Issue #107 - August/September 2016 - 52
JEC COMPOSITES MAGAZINE - Issue #107 - August/September 2016 - Construction
JEC COMPOSITES MAGAZINE - Issue #107 - August/September 2016 - 54
JEC COMPOSITES MAGAZINE - Issue #107 - August/September 2016 - Parasports
JEC COMPOSITES MAGAZINE - Issue #107 - August/September 2016 - Sailing
JEC COMPOSITES MAGAZINE - Issue #107 - August/September 2016 - Watersports
JEC COMPOSITES MAGAZINE - Issue #107 - August/September 2016 - Software
JEC COMPOSITES MAGAZINE - Issue #107 - August/September 2016 - Reaction kinetics
JEC COMPOSITES MAGAZINE - Issue #107 - August/September 2016 - 60
JEC COMPOSITES MAGAZINE - Issue #107 - August/September 2016 - 61
JEC COMPOSITES MAGAZINE - Issue #107 - August/September 2016 - 62
JEC COMPOSITES MAGAZINE - Issue #107 - August/September 2016 - 63
JEC COMPOSITES MAGAZINE - Issue #107 - August/September 2016 - 64
JEC COMPOSITES MAGAZINE - Issue #107 - August/September 2016 - 65
JEC COMPOSITES MAGAZINE - Issue #107 - August/September 2016 - Advertisers
JEC COMPOSITES MAGAZINE - Issue #107 - August/September 2016 - 67
https://www.nxtbook.fr/newpress/jeccomposites/jcm2007_135
https://www.nxtbook.fr/newpress/jeccomposites/jcm_2020_Q1_Innovation_Report
https://www.nxtbook.fr/newpress/jeccomposites/jcm2005_Special_Issue3
https://www.nxtbook.fr/newpress/jeccomposites/jcm2005_134
https://www.nxtbook.fr/newpress/jeccomposites/jcm2003_133
https://www.nxtbook.fr/newpress/jeccomposites/jcm2001_132
https://www.nxtbook.fr/newpress/jeccomposites/jcm1911_Special_Issue2
https://www.nxtbook.fr/newpress/jeccomposites/jcm1911_131
https://www.nxtbook.fr/newpress/jeccomposites/jcm1909_130
https://www.nxtbook.fr/newpress/jeccomposites/jcm1907_129
https://www.nxtbook.fr/newpress/jeccomposites/jcm1905_128
https://www.nxtbook.fr/newpress/jeccomposites/jcm1903_Special_Issue1
https://www.nxtbook.fr/newpress/jeccomposites/jcm1903_127
https://www.nxtbook.fr/newpress/jeccomposites/jcm1901_126
https://www.nxtbook.fr/newpress/jeccomposites/jcm1811_125
https://www.nxtbook.fr/newpress/jeccomposites/jcm1810_124
https://www.nxtbook.fr/newpress/jeccomposites/jcm1808_123
https://www.nxtbook.fr/newpress/jeccomposites/jcm1807_122
https://www.nxtbook.fr/newpress/jeccomposites/jcm1805_121
https://www.nxtbook.fr/newpress/jeccomposites/jcm1804_120
https://www.nxtbook.fr/newpress/jeccomposites/jcm1803_119
https://www.nxtbook.fr/newpress/jeccomposites/jcm1802_119-Supplement_Innovation_Report
https://www.nxtbook.fr/newpress/jeccomposites/jcm1801_118
https://www.nxtbook.fr/newpress/jeccomposites/jcm1711_117
https://www.nxtbook.fr/newpress/jeccomposites/jcm1710_116
https://www.nxtbook.fr/newpress/jeccomposites/jcm1708_115
https://www.nxtbook.fr/newpress/jeccomposites/jcm1707_114
https://www.nxtbook.fr/newpress/jeccomposites/jcm1706_113
https://www.nxtbook.fr/newpress/jeccomposites/jcm1704_112
https://www.nxtbook.fr/newpress/jeccomposites/jcm1703_111
https://www.nxtbook.fr/newpress/jeccomposites/jcm1701_110
https://www.nxtbook.fr/newpress/jeccomposites/jcm1611_109
https://www.nxtbook.fr/newpress/jeccomposites/jcm1610_108
https://www.nxtbook.fr/newpress/jeccomposites/jcm1608_107
https://www.nxtbook.fr/newpress/jeccomposites/jcm1607_106
https://www.nxtbook.fr/newpress/jeccomposites/jcm1605_105
https://www.nxtbook.fr/newpress/jeccomposites/jcm1604_104
https://www.nxtbook.fr/newpress/jeccomposites/jcm1603_103
https://www.nxtbook.fr/newpress/jeccomposites/jcm1601_102
https://www.nxtbook.fr/newpress/jeccomposites/jcm1511_101
https://www.nxtbook.fr/newpress/jeccomposites/jcm1510_100
https://www.nxtbook.fr/newpress/jeccomposites/jcm1509_99
https://www.nxtbook.fr/newpress/jeccomposites/jcm1507_98
https://www.nxtbook.fr/newpress/jeccomposites/jcm1505_97
https://www.nxtbook.fr/newpress/jeccomposites/jcm1504_96
https://www.nxtbook.com/newpress/jeccomposites/jcm1503_95
https://www.nxtbook.com/newpress/jeccomposites/jcm1501_94
https://www.nxtbook.com/newpress/jeccomposites/jcm1412_93
https://www.nxtbook.com/newpress/jeccomposites/jcm1410_92
https://www.nxtbook.com/newpress/jeccomposites/jcm1409_91
https://www.nxtbook.com/newpress/jeccomposites/jcm1406_90
https://www.nxtbook.com/newpress/jeccomposites/jcm1405_89
https://www.nxtbook.com/newpress/jeccomposites/jcm1404_88
https://www.nxtbook.com/newpress/jeccomposites/jcm1403_87
https://www.nxtbook.com/newpress/jeccomposites/jcm1401_86
https://www.nxtbook.com/newpress/jeccomposites/jcm1311_85
https://www.nxtbook.com/newpress/jeccomposites/jcm1310_84
https://www.nxtbook.com/newpress/jeccomposites/jcm1308_83
https://www.nxtbook.com/newpress/jeccomposites/jcm1307_82
https://www.nxtbook.com/newpress/jeccomposites/jcm1305_81
https://www.nxtbook.com/newpress/jeccomposites/jcm1304_80
https://www.nxtbook.com/newpress/jeccomposites/jcm1303_79
https://www.nxtbook.com/newpress/jeccomposites/jcm1301_78
https://www.nxtbook.com/newpress/jeccomposites/jcm1212_77
https://www.nxtbook.com/newpress/jeccomposites/jcm1210_76
https://www.nxtbook.com/newpress/jeccomposites/jcm1208_75
https://www.nxtbook.com/newpress/jeccomposites/jcm1207_74
https://www.nxtbook.com/newpress/jeccomposites/jcm1206_73
https://www.nxtbook.com/newpress/jeccomposites/jcm1204_72
https://www.nxtbook.com/newpress/jeccomposites/jcm1203_71
https://www.nxtbook.com/newpress/jeccomposites/jcm1201_70
https://www.nxtbook.com/newpress/jeccomposites/jcm1111_69
https://www.nxtbook.com/newpress/jeccomposites/jcm1110_68
https://www.nxtbook.com/newpress/jeccomposites/jcm1108_67
https://www.nxtbook.com/newpress/jeccomposites/jcm1107_66
https://www.nxtbook.com/newpress/jeccomposites/jcm1105_65
https://www.nxtbook.com/newpress/jeccomposites/jcm1104_64
https://www.nxtbook.com/newpress/jeccomposites/jcm1103_63
https://www.nxtbook.com/newpress/jeccomposites/jcm1101_62
https://www.nxtbook.com/newpress/jeccomposites/jcm1011_61
https://www.nxtbook.com/newpress/jeccomposites/jcm1010_60
https://www.nxtbook.com/newpress/jeccomposites/jcm1009_59
https://www.nxtbook.com/newpress/jeccomposites/jcm1006_58
https://www.nxtbook.com/newpress/jeccomposites/jcm1005_57
https://www.nxtbook.com/newpress/jeccomposites/jcm1004_56
https://www.nxtbook.com/newpress/jeccomposites/jcm1003_55
https://www.nxtbook.com/newpress/jeccomposites/jcm1001_54
https://www.nxtbook.com/newpress/jeccomposites/jcm0911_53
https://www.nxtbook.com/newpress/jeccomposites/jcm0910_52
https://www.nxtbook.com/newpress/jeccomposites/jcm0909_51
https://www.nxtbook.com/newpress/jeccomposites/jcm0907-08_50
https://www.nxtbook.com/newpress/jeccomposites/jcm0906_49
https://www.nxtbook.com/newpress/jeccomposites/jcm0904_48
https://www.nxtbook.com/newpress/jeccomposites/jcm0903_47
https://www.nxtbook.com/newpress/jeccomposites/jcm0901_46
https://www.nxtbook.com/newpress/jeccomposites/jcm0811_45
https://www.nxtbook.com/newpress/jeccomposites/jcm0810_44
https://www.nxtbook.com/newpress/jeccomposites/jcm0809_43
https://www.nxtbook.com/newpress/jeccomposites/jcm0807_42
https://www.nxtbook.com/newpress/jeccomposites/jcm0806_41
https://www.nxtbook.com/newpress/jeccomposites/jcm0805_40
https://www.nxtbook.com/newpress/jeccomposites/jcm0803_39
https://www.nxtbook.com/newpress/jeccomposites/jcm0801_38
https://www.nxtbook.com/newpress/jeccomposites/jcm0712_37
https://www.nxtbook.com/newpress/jeccomposites/jcm0710_36
https://www.nxtbook.com/newpress/jeccomposites/jcm0709_35
https://www.nxtbook.com/newpress/jeccomposites/jcm0707_34
https://www.nxtbook.com/newpress/jeccomposites/jcm0706_33
https://www.nxtbookmedia.com