Synthesis And Application Of Crosslinker TETS

A novel crosslinking agent TETS was proposed and the synthesis & applications ofthe crosslinker were wholly studied in this paper.Crosslinker TETS (2,2',2"-nitrilo-triethylthiosulphate) is a kind of Bunte salt. Itcould be prepared from the reaction of TES (2,2',2"-nitrilo-triethylsulphate) andthiosulphate (Na₂S₂O₃). There are three Bunte groups and a tertiary amine group in themolecule. TETS easily takes the crosslinking reaction with the hydroxyl group incellulosic fibre or the amino group in protein fibre in alkaline condition. It features strongcrossing ability, good stability of storage, simple process of synthesis, easily soluble inwater, and non- formaldehyde & other harmful substances during its synthesis andapplication.Capillary electrophoresis analysis (CE) was used to trace and control the syntheticreaction, confirm the synthetic mechanism, optimize the process, monitor the separationeffect, analyze the hydrolysis of samples, quantify and characterize the aim resultant. Aseparation method namely "hot and cold filtration with ethanol" was proposed whichresolved the problem of separating TETS from the side resultant sulphate. The objectiveproduct was obtained successfully in the end. By combining the CE and Raman spectraanalysis, the objective substance TETS was characterized and identified.The stabilization to heat, alkali, acids, and hydrolysis of TETS were studied. Themechanism of cross reaction between TETS and cellulosic fibre was speculated accordingto the similar researches from literatures. It is assumed that TETS molecule firstlygenerates an aziridinum ring by eliminating the three leaving groups (-OSO3- groups)sequentially in alkaline environment. Then, the nucleophiles (hydroxyl in cellulose fibreor amino group in protein fibre) would attack and open the aziridinium ring, finishing thesubstitution reaction between TETS and fibres. The crosslinkage bond is testified byinfra-red analysis, element analysis for nitrogen and sulphate.A series of experiments and studies were carried out in the fields of durable-pressfinish of cotton fabric, cellulose modifying to improve dyeing properties, wet strength improving of kraft paper and corrugated paper, anti-fibrillating finish of Lyocell fibre, wetstrength improving of bamboo fibre, wrinkle resistant finish of silk fabric,anti-weight-loss finish of pupa protein fibre etc. Some new testing methods wereproposed. Optimum processes were determined. Theoretical explanations to somephenomena were described. Some novel fields are opened and supplied for thedevelopment and application of the crosslinker TETS.The main conclusions drawn from researches to TETS application are as follows:1) Obvious wrinkle resistant properties for cotton fabric are produced after TETSfinishing: The elasticity of the fabric can reach the level as high as the product oftraditional resin finishing and the crease recovery angle is high to 270℃; the retention ofstrength gets more improved and reached 75% or so; washing resistance is better than thatof traditional resin; but the whiteness decreases a little.The optimum process parameters of TETS treatment to cotton fabric for the durablepress finishing are determined by orthogonal experiments: TETS concentration 100g/L,pH 9.5, baking temperature 170℃, baking time 3 min.The causes that the fabric treated by TETS has higher strength retention were studied.It is testified that there are two aspects which result in the strength loss in traditional sourcross process: one is the crosslink effect, another is the sour effect. The alkalinecrosslinking of TETS would avert cellulose hydrolysis by the sour catalysis, so higherstrength retention comes into being.2) TETS is an aminating agent with crosslinking function. The dyeing properties ofcotton fabric modified by TETS will greatly be improved when dyed with reactive dyes:colour yield is obviously higher; percentage of exhaustion and fixation increase a lot;colour fastness to rubbing is improved remarkably; washing resistant is better as well; butlight fastness gets lower; ability of migrating and leveling dyeing deteriorate, which needsto be researched further next.DMF decolouration experiment shows that the covalence between reactive dyes andcellulose is able to form even dyeing in sour bath and non-salt.Crosslinker TETS supplies a new way to modify cellulosic fibre by amination. It provides a new method of dyeing in neutral (or sour) and non-salt as well.3) The wet tensile strength for papers increases greatly after TETS treatment. Thewet tensile strength of kraft paper is 5 to 6 times higher than that of paper untreated byTETS. The wet/dry strength ratio is high to 50-60%, comparing the ratio of 9% foruntreated paper. But the elongation rate and the folding resistance decrease a lot.The optimum process parameters for TETS wet strength improving finish to Kraftpaper are: TETS concentration 150g/L, pH 9.5, baking temperature 170℃, baking time 3min.Comparing with the traditional resin such as hexahydroxymethyl trimeric cyanamideand F-CL resin (a modified 2D resin), the wet/dry strength ratio, the dry strength and thefolding resistance of Kraft paper treated by TETS are all higher. Good finish effect wasalso obtained in corrugated paper and common filter paper. The wet/dry strength ratioincreases from less than 10% to above 25%. The wet strength in corrugated paper is even8 times higher than that of untreated paper. The decrease of folding resistance gets lower.So TETS is a promising species in wet strength agents.4) In anti-fibrillating finish of Lyocell fibre by TETS treatment, a new way tofibrillate the fabric with the fuzzing and pilling device is suggested. The grade ofanti-fibrillation is greatly raised from 1-2 to 3-4 grade after TETS treatment.5) In TETS wet strength improving of bamboo knitted fabric, the change of burstingstrength after TETS finish was used to evaluate the finish effect. The experiment showsthat both wet and dry bursting strength are higher than those untreated by TETSespecially that the wet strength rises near 20% and the wet/dry strength ratio enhancesfrom 45.3 to 64.6%.6) In anti-weight-loss finish of pupa protein fibre by TETS, a certain degree ofimprovement was achieved to all the three weight loss treatments with water, base andacid. Both weight and strength loss rate get lower.7) In wrinkle resistant finish of silk fabric, the wet and dry crease recovery anglesare improved after TETS treatment, but not as obvious as cotton fabric.The creative points in the paper are as follow: Firstly, the structure of the crosslinkerTETS is novel and hasn't been seen in public journals. Secondly, capillary electrophoresis the synthetic reaction which should be the first time in domestic chemical field. Thirdly,the applications of crosslinker TETS in textile fibre, dyeing and finishing, paper makingare studied systematically that provide some new application fields and processes.CUI Shuling (Chemistry and chemical engineering)Supervised by: Prof. SONG Xin-yuan...