KETANGGUHAN IMPAK DAN KEKUATAN TARIK KOMPOSIT FIBERGLASS/CLAY FILLER BERMATRIKS UNSATURATED POLYESTER BQTN-EX 157

Komposit berpenguat fiberglass memiliki kekuatan yang tinggi, kaku, ringan, serta tahan terhadap korosi sehingga cukup potensial apabila dikembangkan sebagai material alternatif untuk aplikasi bodi kendaraan bermotor. Pada penelitian sebelumnya, peningkatan ketahanan termal komposit diupayakan dengan penambahan 5% fraksi volume clay filler yang memiliki kemampuan hambat bakar cukup baik. Di sisi lain, berkurangnya fraksi volume resin akibat penambahan clay filler mengurangi kemampuan matriks dalam mengikat material penyusun lainnya. Hal tersebut menjadi alasan dilakukannya studi lebih lanjut mengenai pengaruh penambahan clay filler terhadap sifat mekanis komposit fiberglass bermatriks polimer.  Fiberglass jenis Chopped Strand Mat (CSM) dipilih sebagai penguat, resin unsaturated polyester dengan merk dagang BQTN-EX 157 sebagai pengikat, serta clay jenis bentonit sebagai filler. Metode kombinasi close mold dipilih pada pembuatan sampel uji. Jenis pengujian mekanis yang dilakukan meliputi uji impak dan uji tarik. ASTM D4812 dipilih sebagai standar uji impak sedangkan ASTM D638-02 dipilih sebagai standar uji tarik. Hasil dari pengujian impak menunjukan bahwa komposit fiberglass tanpa penambahan 5% fraksi volume clay filler memiliki nilai ketangguhan impak dan kekuatan tarik lebih tinggi bila dibandingkan dengan komposit fiberglass dengan penambahan 5% fraksi volume clay filler. Pengamatan kegagalan mekanis ditinjau dari foto makro patahan spesimen pada pengujian impak dan tarik. Hasil dari analisa foto makro menunjukan bahwa komposit fiberglass dengan clay filler  yang telah diuji impak mengalami patahan ulet dan getas. Sedangkan hasil pengujian tarik menunjukkan terjadinyafiber pull out, void, matrik cracking yang menjadi sebab melemahnya sifat mekanis komposit.
 
Fiberglass reinforced composites have high strength, stiffness, lightweight, and good resistance to corrosion so that they have the potential to be developed as an alternative material for motor vehicle body applications. In previous studies, an increase in the thermal resistance of composites was attempted by the addition of 5% volume fraction of clay filler which has a fairly good fire resistance capability. On the other hand, the reduced matrix volume fraction due to the addition of clay fillers reduces the ability of the matrix to bind to other constituent materials. This is the reason for further studies on the effect of adding clay filler to the mechanical properties of polymer matrix composites. Chopped Strand Mat (CSM) type fiberglass was chosen as reinforcement, thermoset resin with trademark BQTN-EX 157 as the binder, and bentonite type clay as a filler. A close mold combination method was chosen in making the test sample. The types of mechanical testing carried out include Impak and tensile. ASTM D4812 was chosen as the Impak test standard while ASTM D638-02 was chosen as the tensile test standard. The results of the Impak testing show that fiberglass composites without the addition of 5% volume fraction of clay filler have higher Impak toughness and tensile strength compared to fiberglass composites with the addition of 5% volume fraction of clay filler. Observation of mechanical failure in terms of macro photographs of spesimen fractures in Impak and tensile testing. The results of the macro-photo analysis showed that the fiberglass composite with clay filler that had been tested had experienced ductile and brittle fracture. While the results of tensile testing show the occurrence of fibers pull out, voids, matrix cracking which is the cause of the weakening of the mechanical properties of the composite.