Priprava funkcionalnih poliamidnih tekstilij s povečano termično stabilnostjo

Šehić, Alisa (author), Simončič, Barbara (mentor)

V doktorski disertaciji so bile pripravljene funkcionalne poliamidne tekstilije s povečano termično stabilnostjo z izvedbo treh različnih postopkov kemijske modifikacije poliamidnih 6 (PA6) vlaken, in sicer z nanosom ognjevarne apreture s kombinacijo 10-(2-trimetoksisilil-etil)-9-hidro-9-oksa-10-fosfafenatren-10-oksida (DOPO) in tetraetoksisilana (TEOS) na ploskovno tekstilijo, oblikovanjem kompozitnih filamentnih prej iz taline z vključenimi ognjevarnimi sredstvi (OG) melamin cianuratom (MeCy), aluminijevim dietilfosfinatom (AlPi), natrijevim aluminijevim silikatom (SASi), ogljikovimi nanocevkami (CNT) in ogljikovimi sajami (CB) ter oblikovanjem preje iz taline iz novo sintetiziranega kopolimera PA6 z vključeno ognjevarno stransko skupino DOPO (PA/DCA). Iz rezultatov raziskave je razvidno, da je prisotnost apreture DOPO-TEOS upočasnila hitrost termo-oksidativnega (TO) razpada PA6 in povečala količino pooglenelega ostanka, kar potrjuje povečanje termične stabilnosti. Apretura je utrdila strukturo vzorca ter s tem zaustavila odtekanje taline med gorenjem, ni pa preprečila gorenja PA6. Med OG-sredstvi, dodanimi v talino pri oblikovanju kompozitne preje, je bil najučinkovitejši MeCy, ki je v največji meri znižal temperaturo TO-razpada PA6 v prvem koraku razpada ter povečal stabilnost pooglenelega ostanka pri 800 °C. Prisotnost MeCy je ob umiku ognja povzročila takojšnjo ugasnitev gorenja preje. Medtem ko sta SASi in CB v kombinaciji z MeCy delovala vzajemno, pa sta dodatka AlPi in CNT v mešanici z MeCy sicer povečala TO-stabilnost kompozitnih prej, vendar tudi poslabšala ognjevarno delovanje MeCy. Prisotnost DOPO v kopolimerni preji je povzročila znižanje temperature začetka TO-razpada PA/DCA, znižanje temperature razpada v prvem koraku ter rahlo zvišanje temperature razpada v drugem koraku v primerjavi s PA6, vplivala pa je tudi na zmanjšanje količine pooglenelega ostanka. To nakazuje na delovanje sredstva DOPO v plinasti fazi. Čas gorenja kopolimerne preje PA/DCA se je močno zmanjšal v primerjavi s PA6, vendar pa talina, ki je odtekala od vzorca tekom gorenja, ni bila samo-ugasljiva. Ti rezultati so bili slabši v primerjavi s folijami, pripravljenimi iz PA/DCA, pri katerih odtekajoča talina kopolimera ni gorela. Dodatek vseh OG-sredstev pri oblikovanju preje iz taline je povečal stopnjo kristalinosti preje in nekoliko znižal njene natezne lastnosti.

• Language: Slovenian
• Keywords: poliamid 6, ognjevarna sredstva, kompozitna filamentna preja, kopolimer poliamid 6, apretiranje, oblikovanje iz taline, kemijska modifikacija
• Work type: Doctoral dissertation
• Organization: NTF - Faculty of Natural Sciences and Engineering
• Year: 2018
• PID: 20.500.12556/RUL-104874
• Publication date in RUL: 14.10.2018

Secondary language

• Language: English
• Title: Preparation of functional polyamide textiles with increased thermal stability

Abstract

In the doctoral dissertation, functional polyamide textiles with increased thermal stability were prepared by three processes of chemical modification of polyamide 6 (PA6) fibers, by sol-gel application of combination of flame retardants 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide-modified vinyl trialkoxysilane (DOPO–VTS) and tetraethoxysilane (TEOS) onto flat textiles, with melt spinning process of filament yarn samples with incorporated flame retardant (FR) additives melamine cyanurate (MeCy), aluminium diethylphosphinate (AlPi), sodium aluminosilicate (SASi), carbon nanotubes (CNT) and carbon black (CB), and melt spinning of the newly synthesized PA6 copolymer with a directly included flame retardant group DOPO (PA/DCA) on the polyamide chain. The results indicate that the presence of the sol-gel finishing DOPO-TEOS reduced PA6 decomposition rate and favored char formation, which confirms an increase in thermo-oxidative (TO) stability. The presence of the coating reinforce the fibre structure, stopped melt dripping but did not prevent the burning of PA6. FR additive MeCy had the biggest flame retardant influence on the PA6 filament yarns by decreasing the onset temperature of thermo-oxidative and increasing char stability at 800 °C The presence of MeCy completely stopped the flaming combustion of the filament. While SASi and CB interacted with MeCy, the addition of AlPi and CNT in a mixture with MeCy inhibit flame retardant properties of MeCy and only slightly improve TO stability of composite filament yarn samples. The presence of DOPO in copolymer caused a decrease of the onset temperature of the TO-decomposition of PA/DCA, a decrease of the decomposition temperature of the first step of degradation, and a slight increase of the temperature of the decomposition of the second step compared to PA6 and influence in the reduction of amount of residue. This indicates the operation of DOPO in the gas phase. The burning time of the PA/DCA copolymer yarn sample was significantly reduced compared to the burning of PA6 yarn, but the dripping melt of the copolymer was not self-extinguishing. These results were not as good as on films prepared from PA/DCA, where the dripping melt of the copolymer did not burn. The addition of all FR additives increased the degree of crystallinity of the yarn and slightly reduced its tensile properties

• Keywords: polyamide 6, flame retardants, composite filament yarns, copolymer polyamide 6, melt spinning, chemical modification