Abstract:
l")ta~lic polypropylene (iPPJ with Bijoyp'" white elay (BWC) as filler (il'l'-BWC)
were fabri~alcd by a double- molding tecbnique. Thc compo,ile, wcrc cxamined by
asscssing ,urfacc morphology, mcchanical properties, thermal properlics, direct
currenl (DC) and alternaling current (AC) electrical properlies. Scanning eleclron
mi~rographs show thaI thc surtace of lhe iPP sample is ,moolh and the surfaces of
compo,il~, become slightly rough and pale c"lo"
Thc impro,'~menl of some mechanical propel1ie; of lhc BWe filled iPP-BWe
compositGs sllch as Young',1 modulus and microhardness were "h,erved whereas the
e1ongatioll at hreak and tensile strellglh were decrea..ed with the increa,e oj" BWC.
'1he thermal behavior ofiPP-BWC composites wa, analyzed by TGA and DT A. It is
,een tliat the melting lemperature (1"m)does llot show any noticeable change bllt the
degradation temperature (T oj increases with thc increase of filler. Analysis of TCiA
,how; that the neat if'l' sample is seen to be thennally stable up to 416°C whereas
the 30 wl% BWC-Ioaded sample shows the maximum thennal stability at ahout 450
"C.
The current -voltage relationship ofthc composites were studied in the vollage rangc
from II to 120 V al ,Iiflerent temperature,. It is observed that ~lLrr~nt"voltage curve'
Ihow ohmtc behavior in thc lower voltage region. Thc DC conductivily ill~rcascs
with illcrca,ing filler content and lempcmture. The acti,alion cncrgy of all lhe
s~mples has high~r value in high temperature region than those at low tempcmture
regioll ,
'1he dielectri~ ~onstant measured over a freyueocy range of 1000 117-1 MHz alld ill
thc temperat\lre range 01'299-373 K showed dependcnce on ti"cquency, temperalure
and conccntration of IJWC in the ~ompositcs. It is obsel"\'ed thaI dielcelric constant
decrca,es with freqllency_ The AC condllctivity increases with frequency and
temperature, A ,ignificant change of dielectri~ constant is shown ill the composites
with the increase of filler loading. The activation energy ealcillated from the plot,
bctween AC conductivity and lempcrature ,how, that it is low at low temperature
r~gioll and high at higher temperature region.