11.12.2012 Views

Nondestructive testing of defects in adhesive joints

Nondestructive testing of defects in adhesive joints

Nondestructive testing of defects in adhesive joints

SHOW MORE
SHOW LESS

You also want an ePaper? Increase the reach of your titles

YUMPU automatically turns print PDFs into web optimized ePapers that Google loves.

Table2. Formulation for Peroxide cure Table3.Formulation for<br />

Specific cur<strong>in</strong>g system<br />

Result and discussion;<br />

Gel Fraction<br />

The gel fraction is higher for silicone rubber compared to FKM rubber and change <strong>in</strong> gel<br />

fraction with radiation dosage is more pronounced <strong>in</strong> precipitated silica filled systems<br />

compared to fumed ones where changes are only marg<strong>in</strong>al. The gel fraction level is almost<br />

same for chemical cur<strong>in</strong>g and EB cur<strong>in</strong>g methods for both the rubbers as presented <strong>in</strong><br />

Figures 1(a)&1(b).<br />

Mechanical Properties<br />

Hardness<br />

The hardness <strong>of</strong> both fluorocarbon and silicone rubber when re<strong>in</strong>forced by precipitated<br />

silica and EB cured <strong>in</strong>crease with <strong>in</strong>creas<strong>in</strong>g irradiation dosage up to 15 MRads (figure<br />

2(a)) followed by marg<strong>in</strong>al reversion.<br />

Gel fraction (%)<br />

Ingredient Q Q<br />

Precipitated Silica(phr) 20 -<br />

Fumed silica (phr) - 20<br />

TQ (phr) 2 2<br />

Sunpar Oil (phr) 2 2<br />

DCP 5 5<br />

Si-69 2 2<br />

100<br />

98<br />

96<br />

94<br />

92<br />

Q+Ppt silica<br />

Q+fumed silica<br />

FKM+Ppt silica<br />

FKM+fumed silica<br />

90<br />

5 10 15 20 25<br />

Irradiation dosage (MRads)<br />

Gel Fraction (%)<br />

100<br />

80<br />

60<br />

40<br />

20<br />

0<br />

Ingredient FKM FKM<br />

MgO (phr) 6 6<br />

Precipitated Silica(phr) 20 -<br />

Fumed silica (phr) - 20<br />

Sunpar Oil (phr) 2 2<br />

Calcium hydroxide 3 3<br />

Q+ Ppt Silica Q+ Fumed Silica FKM + Ppt Silica FKM+fumed Silica<br />

X Axis Title<br />

EB Cure<br />

Chemical Cure<br />

Figure 1 (a): Variation <strong>in</strong> Gel Fraction Figure 1 (b): Comparison <strong>of</strong> best Gel Fraction<br />

with <strong>in</strong>creas<strong>in</strong>g irradiation dosage obta<strong>in</strong>ed <strong>of</strong> irradiated sample with chemical cure

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!