Industrial Precursors from Agricultural Wastes

Abstract

Potential copolymers as  industrial precursors  were  developed  from  Carica papaya seeds  oil.    

Carica  papaya   fruits  were  collected  in Ibadan, Nigeria.   Seed oils of this fruit were extracted using n-hexane and concentrated. Phenolated carica- papaya  biopolymer(PCPB)  was   prepared by polymerizing the oil with phenol through  cationic polymerization method. Polyacrylamide(PAA)  and  Polyacrylonitrile(PAN) were  prepared  through free  radical polymerization technique.  The copolymers    were prepared by   polymerizing PCPB, PAA and PAN to produce PCPB-PAA and PCPB-PAN.  They were  characterized  using FTIR for  functional groups  modifications,  ¹H-NMR for  changes  in  chemical environments    and  Viscometry  techniques for  mean molecular  weight  determination.  

The   oil yield is 32.22%.  Iodine value(gI₂/100g)   is 99.55±0.38 and  61.98±0.06   for oil and    PCPB   respectively.  FTIR  band shifts  at 1552.75cm^-1 confirm  C=C stretch  of aromatics in PCPB. PAA formation was confirmed with C=O stretch at 1680.00cm^-1. Peak at  2250cm^-1 confirm C≡N of  PAN.     Peak at 3474.24cm^-1  confirm    N-H  stretching vibration of amides that  suggest  polyester-amide copolymer. C-N bond occurred at 2034.28cm^-1 to establishe PCPB-PAN copolymer. The  ¹H-NMR   spectra  showed  peaks  at  δppm, δ8.11ppm(s, 2H) to confirm  aromatics in  PCPB. δppm  at 7.18 confirmed  peptide  protons  in PAA. δ 7.18(s, 1H) and  6.86(s, 3H) suggest that  PAA was  grafted  to PCPB backbone.  δ4.89ppm(q, J = 8.8 Hz, 1H) suggests  the  presence  of  substituted  nitrile in PCPB-PAN. Both FTIR  and  ¹H-NMR results    confirmed  formation  of    new  copolymers.  The mean molecular  weight(g/mol)  for   PCPB, PCPB-PAA  and PCPB-PAN     are   7.482x10⁹, 1.062x10¹² and  1.135x 10¹² respectively to affirm the  grafting processes.  

The results suggest that ecologically friendly industrial precursors are feasible from Agricultural wastes.