Thermal gravimetric analysis of fiber glass
Z. U. Haq1, A. K. Khattak1, Z. Khan1, F. U. Khan1, A. Ather1, S. U. Khan2
1Institute of Chemical Sciences, Gomal University, Dera Ismail Khan, Pakistan
2Department of Chemistry, University of Science & Technology, Bannu, KPK, Pakistan
*Corresponding Author E-mail: zia.hassan80@yahoo.com
ABSTRACT:
Aluminized E-glass fiber reinforced polyvinyl alcohol composites, originally formulated for enhanced electrical shielding and thermal properties were evaluated in terms of their thermal performance. The role of temperature increase required for degradation of these specimens analyzed using a TGA ( thermogravimetric analyzer). The different samples were heated from surrounding temperature to 500 1C at a heating rate of 20 1C/min. The various specimens were decomposed by using dry nitrogen (N2) at a flow rate of 40 ml/min to yield solid material and gases. These aluminized E-glass composites were compared with the unreinforced composite and unmetallised E-glass. During increase of temperature the major weight loss were noted between 200 and 400 1C. The unreinforced polyvinyl alcohol (PVA) had lost a more weight loss, 1.25%/1C, occurring at 360 1C. For the unmetallised and aluminized E-glass composites, the maximum rate of weight loss was 0.55 and 0.34%/1C, respectively. Experimental results show the degradation of the aluminized E-glass composites obtained from TGA tests is higher compared to those of unmetallised E-glass fibre and unreinforced polyester composite. This improvement is correlated to the aluminum coating.
KEYWORDS: Aluminized fiber; Thermogravimetric analysis; Fiber degradation
In the last few years aluminum based composite material has become popular because it is based In automotive industries and aerospace.90% of the reinforcement is composed of the glass fiber and is also usable in structural reinforcement plastic applications1. For decades the aluminized glass fiber is used in various technologies. Jet fighter deceives rival missiles by the help of such fibers up till now aluminized E-glass was only used for defense purposes. To modify or improve mechanical and physical characteristics of the fiber will be our great achievement. By increase the thermal conductivity of the aluminized glass fiber we can increase its electric and thermal potentia1,2.
Thermal analysis (heat or temperature) which takes a number of analytical process in which the characteristics of polymeric material are measures as a function of temperature. Dynamic Thermal Gravimetric (TGA) takes a physical measurement while due to temperature the weight loss is recorded, while the process is done in a control temperature. In polymer production thermal stability of a polymeric material should be judged so in a degradation. The damaging of condensation polymers can happened by mixed decomposition or at reactive sites in the polymeric chain, which relies on the kind or quality of the polymeric material, while de-polymerization reactions will monomer formation are characteristic of vinyl polymer structure3.so the main degradation reaction will be due to polymer structure and heating process. In the degradation of poly vinyl alcohol inter molecular alcohol exchange and b-hydrogen transfer are the two methods due to these the early steps of the thermal decomposition are carried out. Although in poly vinyl alcohol, in the first thermal cleavage the whole process is done there3,4. Thermogravimetric analysis (TGA) is an important thermal analysis strategy and is used for the characterization of polymeric material. According to some research, during investigation of degradation mechanism, although, the thermos analytical curves give only a handful of information about the whole process, and cannot distinguish among partial reactions. More ever from first and after coming derivatives you can take further information and to study deeply the degradation mechanism is not possible. The detailed keinetic analysis has given a lot of information by the help of mode free determination of the activation energy3–5.
In the recent times we have not made progress in the work of polymer composite material reinforced by aluminized E-glass fiber, but in the field of work on glass/ poly vinyl alcohol we have made a lot of progress6–10. In order to use this new material/composite in our routine use, we must make less the expected damages of this material by mechanical and physical property, some modie it common with common glass fiber composites11–14. The purpose of this study was to make composites samples by the help of aluminized E-glass fiber and to judge their thermal characteristics. We can found somewhere else the experimental process of the aluminized E-glass fiber composite1.
EXPERIMENTAL:
Test method
TGA was carried out using a TGA Q 50 V6.1 Build 181 TGA. The TGA curves were obtained under dry nitrogen (N2) atmosphere at a flow rate of 40 ml/min and a scanning rate of 20 1C/min.
RESULTS AND DISCUSSION:
The thermal degradation of aluminized E-glass fiber was judged and for the sack of experience put in comparison to unreinforced poly vinyl alcohol and unmetallized E-glass fiber. The first one derivate (DTGA) and the thermograms of aluminized E-glass. Unmatalized E-glass and unreinforced poly vinyl alcohol are indicated in Figs 1 and 2, on after another. The detailed of the important feature of temperature of thermograms and DTGA are given in the shape of table. it is obvious that fig 1 and for the unreinforced poly vinyl alcohol there are several peak occurring between 210 and 350k in the DTG curve, which indicates that the degradation is a two stage process. At 200k the first process begins and reaches to 10% k at 210k. After that the second weight loss process comes and indicates a higher rate of decomposition 1.25% k at almost 360k. the char left for this specimen at 500k was almost 9%. For the unmetalized E-glass sample, at 180k the weight loss starts, and then peakes from DTG of weight loss were seen at almost 210, 340 and 470k, while one in the middle has maximum rate of weight loss is almost at 0.55% k.
The remaining of 58% was discovered/ seen at 500 k. when we take aluminized E-glass sample, we saw the there are two peaks of weigh reduction, the sample began to lose weight after 210k. the sample than reached a maximum rate of 0.24% k at 280 k and atlast, the remaining production was 74% at 500k. this was the highest left after three products.
Fig. 1.- Derivative Themograms.
Fig. 2.- Themograms traces.
Table 1. The characteristic temperatures at elevated weight loss
|
Specimens |
T Onset(1C) |
T10% (1C) |
T25% (1C) |
T50% (1C) |
TEnd(1C) |
MResid(%) |
|
Unreinforced poly vinyle alcohol |
204.7 |
285.5 |
328.7 |
353.6 |
384.4 |
9.83 |
|
Unmetallised E-glass |
239.9 |
315 |
348.9 |
— |
374 |
58.87 |
|
Aluminised E-glass |
282.4 |
336 |
440.4 |
— |
380.2 |
74.58 |
CONCLUSIONS:
The thermal degradation of an aluminized E-glass fiber reinforced poly vinyl alcohol composite has been successfully studied and experimentally compared to unreinforced poly vinyl alcohol and unmetallised E-glass composite. The char yield of the aluminized E-glass fiber composite was found to be higher than that of unmetallised E-glass fiber composite by approximately 26%, and 658% higher than the unreinforced poly vinyl alcohol. The reason is that the presence of the aluminum coating enhances the formation of char and hinders diffusion of volatile decomposition within the composite.
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Received on 12.11.2015 Modified on 19.11.2015
Accepted on 05.12.2015 © AJRC All right reserved
Asian J. Research Chem. 9(1): Jan., 2016; Page 22-24
DOI: 10.5958/0974-4150.2016.00004.3