A simple approach with scale-up potential towards intrinsically flame-retardant biobased co-plasticizer for PVC artificial materials

As an imitation of genuine leather,polyvinyl chloride(PVC)artificial materials are versatile,but suffers from being flammable due to the presence of large amounts of combustible plasticizers.Under such circumstance,intrinsically flame-retardant plasticizers displaying dual functions have been a subject of intensive research interest.However,previous strategies attempting to covalently attach flame-retardant moiety to plasticizers invariably required either expensive starting materials or laborious and tedious procedures,ultimately limiting their scale-up application in industry.In addition,driven by escalating demand of halogen-free flame retardants worldwide from an environmental health perspective,previously reported intrinsically flame-retardant plasticizers were mainly halogenfree,less attractive in PVC artificial material industry simply because PVC itself is a halogen-containing polymer.Here,we report an approach to introduce chlorine moieties into unsaturated fatty acid methyl ester by a simple addition reaction occurring on carbon-carbon double bonds,yielding a chlorine-containing,intrinsically flameretardant bio-plasticizer.When combined with di-(2-ethylhexyl)phthalate(DOP)in PVC formulations,the chlorinated fatty acid methyl ester is qualified as a co-plasticizer while conferring flame retardancy upon the PVC coatings.This approach involves only a one-step procedure that employs renewable fatty acid methyl esters and cheap chlorine gas as raw materials,thus being of great potential to enable intrinsically flame-retardant bioplasticizers on a large scale to manufacture functional PVC artificial materials for application in fire-prone scenarios.

Comparison of tragal perichondrium and COOK artificial material in endoscopic type 1 tympanoplasty

Objective:Various materials have been used for tympanic membrane reconstruction in middle ear surgery.This study aimed to evaluate the difference between the tragal perichondrium and COOK arti-ficial material in patients who underwent endoscopic type 1 tympanoplasty.Method:This retrospective study included patients who underwent endoscopic type 1 tympanoplasty from June 2021 to June 2022 at Sir Run Run Shaw Hospital,Zhejiang University School of Medicine.Patients were divided into group A(tragal perichondrium)and group B(COOK artificial material)ac-cording to the material used in the operation.All patients were followed up for 6 months.The differences in age,gender,operation site,disease course,preoperative air-bone gap(ABG),operation time,blood loss,hearing gain,and wound healing rate were compared between the two groups.Results:This study enrolled 197 patients,with 120 patients in group A and 77 patients in group B.There were no significant differences in age,gender,operation site,disease course,or preoperative ABG be-tween groups A and B(p>0.05).Both groups had significant postoperative improvement in hearing(group A:30.98±9.58 dB vs.17.07±9.92 dB,p<0.001;group B:29.75±7.52 dB vs.14.25±9.07 dB,p<0.001).The mean hearing gain in group A and group B was comparable(14.02±11.91 dB vs.15.50±7.05 dB,p=0.609).The wound healing rates of groups A and B were no differences(93.33%vs.87.01%,p=0.133).The patients in group B had a shorter operation duration(72.57±11.32 min vs.61.86±9.27 min,p=0.045)and less blood loss(12.38±3.7 mL vs.8.10±2.43 mL,p=0.004).Conclusions:Tragal perichondrium and COOK artificial material are reliable for functional and anatomical outcomes in endoscopic type 1 tympanoplasty,and COOK artificial material can save operation time and blood loss in surgery compared to the tragal perichondrium.

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.