THE SYNTHESIS OF A MMA/MAh COPOLYMER AND PROPERTIES OF THE COPOLYMER-BASED GEL POLYMER ELECTROLYTES
Bibliographic record
Abstract
Poly(methyl methacrylate)(PMMA) is one of the matrix polymers commonly used in gel polymer electrolytes,and has been proposed for lithium battery applications.PMMA-based gel polymer electrolytes(GPE) show high ionic conductivity at ambient temperatures.However,low thermal stability and mechanical properties with hard forming free-standing film in gel systems at high organic solvents will limit its application.In order to overcome these problems,methyl methacrylate(MMA)-maleic anhydride(MAh)(P(MMA-co-MAh)) copolymer was prepared,in the copolymer the ring structure of MAh units can improve the thermal stability and mechanical properties,consequently,improving the thermal stability of P(MMA-coMAh)-based gel polymer electrolytes.The copolymer of P(MMA-co-MAh) was synthesized through solution copolymerization with toluene as solvent,2,2′-azobisiobutyronitrile(AIBN) as the initiator,MMA and MAh as the monomers with the molar ratios of MMA∶MAh monomer is 1∶1.The reaction was carried out at 80℃ under nitrogen atmosphere for 8 h.The structure and properties of the copolymer were characterized by Fourier transform infrared spectroscopy(FTIR),()~1H-nuclear magnetic resonance(()~1H-NMR),X-ray diffraction(XRD),gel permeation chromatography(GPC),thermogravimetric analysis(TGA),differential scanning calorimetry(DSC).It was found that the unsaturated bonds existed in both of MMA and MAh(1637 cm~(-1)) disappeared in the copolymer,whereas a strong absorption peak at 950 cm~(-1) for (O)(C)(O)(C)(O) ring stretching vibration of a saturated cyclic five-membered anhydride and a peak at 1445 cm~(-1) for —CO—O—CH_3 stretching vibration of MMA were observed in the FTIR spectrum,respectively.The()~1H-NMR spectrum of P(MMA-co-MAh) copolymer showed four peaks,and the peaks at δ=2.65～3.20 and 3.5～3.8 represent the chemical shift of H for MAh groups and —COOCH_3 groups,respectively,indicating the molecular structure of copolymer P(MMA-co-MAh).The molar ratios of MMA and MAh in the P(MMA-co-MAh) copolymer is 8∶1.XRD showed that the P(MMA-co-MAh) was a typical amorphous polymer,which is beneficial in improvement of ionic conductivity of its GPE.GPC resalts show that the number average molecular weight(M_n) of the copolymer is 6.40×10~4 and the mass average molecular weight(M_w) is 6.68×10~4;the molecular weight distribution(M_w/M_n) is 1.04.The TGA curves show that the thermal degradation temperature of P(MMA-co-MAh) is 300℃,which is higher than that of the pure PMMA polymer.The DSC results of the P(MMA-co-MAh) copolymer reveal that the glass transition temperature(T_g) is 121.3℃,which is higher than that of the pure PMMA.The gel polymer electrolyte was prepared from the P(MMAco-MAh) copolymer,propylene carbonate(PC) and lithium perchlorate.It is found that the GPE can form free-standing films.The ionic conductivity is 3.0×10~(-5) S/cm at room temperature for 45 wt% P(MMA-co-MAh) gel copolymer enlectrolyte with 55 wt% 1 mol/L LiClO_4-PC solution.The ionc conductivity for GPE of P(MMA-co-MAh) copolymer is lower than that of the gel polymer electrolytes of pure PMMA containing 50 wt% PMMA with 50 wt% 1 mol/L LiClO_4-PC solution.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.001 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".