1. Fire properties under heat fluz
THERMAL AND FIRE PROPERTIES OF UNSATURATED POLYESTER RESIN MODIFIED BY FLAME RETARDANT BLEND
B. Cichy (1), E. Kużdżał , M. Nowak,
(1)New Chemical Syntheses Institute, Inorganic Chemistry Division “IChN” in Gliwice
Sowińskiego Street 11, Gliwice , Poland
Phone:+48 32  ,
Introduction
Unsaturated polyester resins (UP) are commonly used for production a number of structural materials which apart from good mechanical features also have flame retarding properties. UP resins are used for producing polyester glass reinforced pipes (GRP) manufactured in a centrifugal casting process. Some UP application require their fire resistance. The polyester composition of reduced flammability may contain multicomponent synergy based mixture additive flame retardants (FR) [1-3].The effect of additive (FR) system on fire, thermal and processing properties of resins compositieswas studied.
Experimental
Tested compositions contains orthophtalic-maleic-propylene unsaturated polyester resin (UP), styren as cross-linking mononer and 40% FR blend. As flame retardants (FR) were used: melamine polyphosphate (MPP), ammonium polyphosphate (APP), aluminum hydroxide (ATH) and expanded graphite (EG).The curing time of compositions with adding MEK peroxide and cobalt naphthenate was examined in 25ºC and 55 ºC for every sample. The influence of the additives on the curing time, thermal decomposition and kinetic parameters of the process was tested using DSC and DTG method. Analyses were conducted under the atmosphere of air (flow of reac-tion gas 80 mL min -1) in open 70-lL alumina crucibles. Thermal decomposition was tested in the temperature range ºC with heating rates 10ºC/min.
The flammability of the samples was evaluated by cone calorimeter test by Institute for Engineering of Polymer Materials and Dyes, Paint and Plastics Department.
Using computer analysis, a number of flammability properties of materials were defined in line according to ISO :2002, part 1 “Reaction to fire tests head release rate, smoke production and mass loss rate” using an external heat flux of a density of 50 kW/m2, and air flow rate of 24 L/s, initiation type of the burning reaction—spark igniter, with a horizontal (in relation to the radiator) orientation of samples.
Fig 1. TG curves of thermal decomposition of resin composition
RESULTS AND DISCUSSION
Introduction of FR blend to UP resin improved the thermokinetic properties of UP compositions. Summary of obtained data is presented in Table.
The addition of retardants affects: reduction of curing time of the resin composition, slight decomposition of cured resin, significant reduction in the amount of heat released during combustion and increase the residue of mineral substances after combustion.
The exothermic peak of thermal decomposition was observed in every run. Enthalpy of the transformation in this case was ca. 55 J/g.
Fig 2. Curing time for various samples - temperature 25oC No
Sample
Curing time [min]
Fire properties under heat fluz
50 kW/m2
Weight loss
30-600°C
25°C
55°C
HRR (average)
kW/m2
ALMR (average)
g/sm2 1
100% cured UP
63.4
18.4
412.9
13.0
99.9% 2
60%UP +
13% MPP + 22% APP + 5% EG
20.4
11.8
85.8
5.8
75.9% 3
10% MPP + 25% ATH + 5% EG
59.5
14.9
80.3
5.0
76.3% 4
35% MPP + 5% EG
44.7
14.2
89.9
6.0
82.9% 5
40%MPP
33.2
13.5
86.2
5.9
85.7%
Fig 3. Curing time for various samples - temperature 55oC
CONCLUSIONS
Referring to obtained data it can be stated that flame retardant additives reduce the curing time and slightly reduce the decomposition temperature. During combustion, the amount of released heat is significantly reduced. The additives increase the quantity of residue after combustion, that is the result of the mineral character of fillers. MPP in combination with other flame retardant was tested and it was observed that even a minor quantity of EG additive intensifies flame retardation effect. Investigated flame retardant significantly enhance fire properties.
ACKNOWLEDGEMENTS
This work was supported by Applied Research Programme of the Polish National Centre for Research and Development, contract number PBS2/B2/7/2013.
REFERENCES
[1] S. Nazare, B. K. Kandola , A. R. Horrocks, Polym. Adv. Technol. 17, (2006) p. 294.
[2] Patent Application PL (2016).
[3] E. Kicko-Walczak, G. Rymarz, I. Gajlewicz, Przem. Chem., 93 (6), (2014) p.914.