Epoxidized methyl ricinoleate bio-plasticizer with a pendant acetate ester for PVC artificial material:circumventing existing limit on achievable migration resistance

Processing polyvinyl chloride(PVC)artificial material requires plasticizer that softens the PVC coating.Currently,utilizing unsaturated fatty acid methyl esters to obtain epoxidized fatty acid methyl ester(EFAME)bio-plasticizers constitutes an environmentally responsible solution to substitute conventional ortho-phthalates that are endocrine disruptors or probable carcinogens.However,commercial EFAMEs,even with the highest epoxy value(ca.5.5-5.8%)so far,still suffer from fast leaching from the PVC matrix,burdening the environment and shortening lifespan of the artificial material.Here,we report a proof-of-principle demonstration of a new strategy to obtain migration-resistant EFAME that harnesses the midchain hydroxyl of methyl ricinoleate and covalently attachment of a pendant acetate ester.Despite a low epoxy value(3.0%),the engineered bio-plasticizer displays significantly suppressed migration in multiple scenarios compared with one conventional EFAME with much higher epoxy value(5.8%).Circumventing the limit confronting previous strategy that highlights the sole contribution of epoxy value to achievable migration resistance,the rationale herein may provide guidance for designing new EFAMEs with comparable performance to ortho-phthalates,thus bringing the old and oft-maligned PVC artificial material industry one step closer to sustainability.

Evaluation of anti-migration properties of biliary covered self-expandable metal stents

AIM: To assess anti-migration potential of six biliary covered self-expandable metal stents(C-SEMSs) by using a newly designed phantom model. METHODS: In the phantom model, the stent was placed in differently sized holes in a silicone wall and retracted with a retraction robot. Resistance force to migration(RFM) was measured by a force gauge on the stent end. Radial force(RF) was measured with a RF measurement machine. Measured flare structure variables were the outer diameter, height, and taper angle of the flare(ODF, HF, and TAF, respectively). Correlations between RFM and RF or flare variables were analyzed using a linear correlated model.RESULTS: Out of the six stents, five stents were braided, the other was laser-cut. The RF and RFM of each stent were expressed as the average of five replicate measurements. For all six stents, RFM and RF decreased as the hole diameter increased. For all six stents, RFM and RF correlated strongly when the stent had not fully expanded. This correlation was not observed in the five braided stents excluding the laser cut stent. For all six stents, there was a strong correlation between RFM and TAF when the stent fully expanded. For the five braided stents, RFM after full stent expansion correlated strongly with all three stent flare structure variables(ODF, HF, and TAF). The laser-cut C-SEMS had higher RFMs than the braided C-SEMSs regardless of expansion state.CONCLUSION: RF was an important anti-migration property when the C-SEMS did not fully expand. Once fully expanded, stent flare structure variables plays an important role in anti-migration.

Application of the Long-Chain Linear Polyester in Plastification of PVC

The plastification modification of poly （vinyl chloride） （PVC） with the long-chain linear polyester （LP） synthesized by linear dodecanedioic acid （DC12） or tetradecanedioic acid （DC14） with different diols is investigated. The processing characteristics, mechanical properties and extraction property of the PVC/LP blends in different solvents （xylene, cyclohexane, ethanol） were also studied in detail. All results were compared with that of the PVC plasticized with dioctyl phthalate （DOP）. The results show that the molecular weight, molecular structure and loading of LP greatly influence the mechanical properties of the PVC/LP blends. The processability and the mechanical properties of PVC plasticized by LP are comparable to those of the corresponding PVC/DOP blends. However, the PVC/LP blends posses much better migration resistance property than the corresponding PVC/DOP blends, which makes the long-chain linear polyester become a very good plasticizer candidate for PVC industry.

Synthesis of Bio-base Plasticizer Using Waste Cooking Oil and Its Performance Testing in Soft Poly(vinyl chloride)Films

Waste cooking oil was modified to prepare bio-base plasticizers(a,b and c)with terephthalic acid,adipic acid and benzoic acid by transesterification,epoxidation and ring opening reactions,respectively.The polyvinyl chloride(PVC)films(a/PVC,b/PVC and c/PVC)were prepared using a,b and c as bio-base plasticizers.The epoxidation and ring opening reactions were mainly investigated through GC-MS analysis.The structures of bio-base plasticizers(a,b and c)were confirmed by Fourier transform infrared spectroscopy(FT-IR),^(1)H NMR and ^(13)C NMR.The mechanical properties of a/PVC were as good as those of PVC films with the dioctyl phthalate(DOP)plasticizer.Meanwhile,the elongation at break of c/PVC reached 422%.The glass transition temperature(Tg)from dynamic mechanical analysis(DMA)was reduced to 30.6℃,45.3℃,23.6℃and 40.6℃,respectively when 40 phr of a,b,c and DOP plasticizer were added.Results of thermogravimetric analysis(TGA)illustrated that the thermal degradation stabilitiy of a/PVC films was better than those of c/PVC and DOP/PVC.The volatility losses of a,b and c were lower than that of the DOP.Bio-base plasticizers a and c exhibited excellent migration resistance in different solutions(distilled water,50%ethanol(w/w)).The FT-IR of PVC films showed that the downfield shifts of the—CH—Cl groups of the PVC plasticized with a and c were greater than that of b/PVC.The bio-base plasticizers b had a better plasticizing effect at low temperature.