CO₂ 对酰基化合物引发2-吡咯烷酮聚合的影响.

陈 晨; 陈 涛; 赵黎明; 邱永隽

The influence of catalyst and CO2 on the synthesis of bio-based poly(γ-aminobutyric acid) (PGABA) was investigated in the presence of an acyl compound initiator. The molecular structure and crystal form of the products were examined using magnetic resonance spectroscopy (1H-NMR), Fourier-transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD). Thermogravimetry (TG) and differential scanning calorimetry (DSC) were used to evaluate the thermal properties of PGABA prepared via different ways. Results indicated that the addition of CO2 had an adverse effect on the yield of PGABA. When the mole fraction of acyl catalyst was fixed at 6% or 7%, the molecular weight increased at first and then decreased with increasing the dosage of CO2 , while the yield decreased successively. When the mole fraction of catalyst was increased to 9%, increasing the dosage of CO2 less affected the molecular weight of PGABA, but the yield kept decreasing. On the other hand, the absence of the initiator dramatically decreased the yield of PGABA in the CO2 containing system. At the different dosages of CO2, the molecular weight rose firstly and then went down with increasing catalyst mole fraction. Such a trend became not evidence at a high dosage of CO2. The impact of catalyst mole fraction on the yield was a little complex. The yield could reach a maximum with increasing the catalyst mole fraction when CO2 mole fraction was less than 13.2%, above which a positive effect of the catalyst on the yield was presented. The crystals of PGABA samples prepared through various methods were all of the α form and independent of the mole fraction of catalyst, initiator, and CO2. Moreover, introducing CO2 less affected the melting point of PGABA, but led to the increase of the thermal decomposition temperature and the improvement of the thermal stability of PGABA.

NUCLEAR magnetic resonance spectroscopy; MOLECULAR structure; MOLE fraction; MELTING points; ACYL compounds

Journal of Functional Polymers, 2020, Vol 33, Issue 3, p290

1008-9357

Academic Journal

10.14133/j.cnki.1008-9357.20190312001