EXPERIMENTAL AND FINITE ELEMENT ANALYSIS OF SOLVENT CAST POLY(LACTIC ACID) THIN FILM BLENDS
Authors: Syed Shaharuddin Sharifah Imihezri , Mukhtar Abdul Rahman , Mohd. Akhir Nur Atiqah , Shaffiar Norhashimah , Othman Maizatulnisa 
Published: December 2019

A combined experimental and finite element analysis () investigation was performed to study the effect of incorporating poly(propylene carbonate)(PPC) and curcumin on the mechanical properties of poly(lactic acid) (PLA). In addition, the chemical interaction and morphological changes brought upon by each subsequent additive were also observed. The addition of PPC at 30 wt% into PLA causes a decrease in strength and modulus by 51% and 68% respectively whilst inducing higher elongation by 74%.  The resultant decrease in strength and modulus of the PLA/PPC blend was recovered by adding a low weight percentage (1 wt%) of curcumin. The images of the fractured surfaces via scanning electron microscope () revealed the brittle-ductile-brittle progression of PLA due to the addition of PPC and curcumin which corroborates the findings from the tensile test. Fourier-transform infrared spectroscopy () revealed that the addition of PPC by 30 wt % resulted in chemical interaction between the carbonyl groups of PLA and PPC  as the C=O peak of PLA slightly shifted to a lower wavenumber. The presence of curcumin peaks however was found to be difficult to be identified in the PLA/PPC/curcumin blend. The simulated results for the stress-strain profile using FEA agreed well with the experimental tensile test profile with a relatively low percentage error of less than 6%. Therefore, it was concluded that for these compositions, the developed model can be used for further simulation works to design biomedical devices.

ABSTRAK: Gabungan penyelidikan secara eksperimen dan analisis unsur terhad (FEA) telah dijalankan bagi mengkaji kesan campuran poli (propilen karbonat) (PPC) dan kurkumin pada sifat mekanikal poli (asid laktik) (PLA). Tambahan, interaksi kimia dan perubahan morfologi pada setiap penambahan berikutnya turut diperhatikan. Penambahan PPC pada 30 wt% ke dalam PLA menyebabkan pengurangan pada tenaga dan modulus sebanyak 51% dan 68% masing-masing sementara menyebabkan kenaikan pemanjangan sebanyak 74%. Hasil pengurangan pada tenaga dan modulus campuran PLA/PPC diseimbangkan dengan mencampurkan peratus kurkumin kurang berat (1 wt%). Melalui mikroskop imbasan elektron (SEM), didapati imej permukaan retak menunjukkan PLA berturutan rapuh-mulur-rapuh disebabkan penambahan PPC dan kurkumin di mana ianya menyokong dapatan kajian ini melalui ujian kekuatan tegangan. Spektroskopi Inframerah Jelmaan Fourier (FTIR) menunjukkan dengan penambahan PPC sebanyak 30 wt %, interaksi kimia antara kumpulan karbonil PLA dan PPC pada puncak C=O PLA telah berubah sedikit kepada nombor gelombang lebih kecil. Walau bagaimanapun, kehadiran puncak kurkumin adalah sukar dikenal pasti dalam campuran PLA/PPC/kurkumin. Dapatan hasil simulasi pada profil strain-tekanan menggunakan FEA adalah sama dengan ujian kekuatan tegangan dengan peratus ralat yang agak rendah iaitu kurang daripada 6%. Oleh itu, komposisi model yang dibangunkan ini adalah sesuai bagi meneruskan kerja-kerja simulasi iaitu bagi mereka bentuk alat biomedikal.