18 TH INTERNATIONAL CONFERENCE ON COMPOSITE MATERIALS SYNTHETIC AND NATURAL DYEING OF WOOD FIBERS IN WOOD-PLASTIC COMPOSITE N. Hongsriphan 1,2* , P. Patanathabutr 1,2 , A. Sirisukpibul 1 1 Department of Materials Science and Engineering, Faculty of Engineering and Industrial Technology, Silpakorn University, Nakhon Pathom, Thailand 2 Center of Excellence for Petroleum, Petrochemical, and Advanced Materials, Bangkok, Thailand * Corresponding author (nattakar@su.ac.th) Keywords : wood-plastic composite, dyeing, direct dye, reactive dye , Sappan 1 Introduction were supplied by Huntsman (Guangdong) Ltd. It is well known that color of wood-plastic Caesalpinia sappan bark was received from a local composite (WPC) changes to lighter after outdoor mill. Other chemicals used were; Sodium chlorite, exposure. Adding pigment is a general remedy to Acetic acid, Sodium sulphate, Sodium carbonate obtain long-lasting appearance of WPC products. In anhydrous, and Aluminium sulphate. All materials textile industry, direct and reactive dyes are were used as received. synthetic dyes which are suitable for cellulosic 2.2 Removing lignin and dyeing dyeing. They not only provide colors to textiles but Method to remove lignin by Sodium chlorite also protect them from photo-degradation and light (NaClO 2 ) was performed following P.A. Ahlgren et fastness. Recently, use of natural dye becomes an al . [1]. Sodium chlorite (NaClO 2 ) of 0.3 g and interest in textile industry due to environmental glacial acetic acid of 0.1 ml, per 1 gram of dry wood concern. There is no much literature reported on and liquor ratio of 15:1 were used to remove lignin dyeing wood flour used in WPC and their influence from wood. Bleaching temperature was set at 70°C on physical and mechanical properties. The aim of for 8 hrs. Treated wood flour was washed in distilled this work is thus to improve appearance of wood- water until pH of water was 7. Original and delignin plastic composite by dyeing delignin wood flour wood flour were determined lignin content in with two types of synthetic dyes and one natural dye accordance to TAPPI T 222 om-98 (Klason lignin). from Caesalpinia sappan bark. Influences of dyes on integrity of wood fibers and WPC’s mechanical Table 1. Characteristics of synthetic dyes. properties with dyed wood fibers were investigated. λ max Scientific Main functional Trade name name group (nm) 2 Experimental Solophenyl CI Direct Amide, Sodium 519 2.1 Materials Bodeaux 3 Red 83.1 sulphonate, BLE Metal complex Rubber wood ( Hevea brasiliensis ) sawdust was ball milled and sieved (200-500 mesh size) to be 31-74 MCT 1 /VS 2 /VS Novacron CI 514 micron in particle size. High density polyethylene Red C-2G Reactive (HDPE, MFI of 20 g/10 min) was kindly supplied by Red 281 PTT Chemical Public Co Ltd., Thailand. Maleated 1 MCT : monochlorotriazine ; polyethelene (MAPE, maleic anhydride content of 0.9 wt%) was purchased from DuPont, USA. Solophenyl Bodeaux 3 BLE (C.I. Direct Red 83.1) 2 VS : vinyl sulphone ; and Novacron Red C-2G (C.I. Reactive Red 281)
Table 1 presents characteristics of two types of with a temperature profile of 150, 160, and 180�C synthetic dyes used in this study. Delignin wood from feeding to die. Original wood, delignin, direct- flour was dyed with CI Direct Red 81.3 of 1% on dyed, reactive dyed, and Sappan-dyed WPC are weight of fiber (%o.w.f.) at liquor ratio 10:1 using denoted as WPC, D-WPC, DR-WPC, RT-WPC, and Sodium sulphate as salt electrolyte. Delignin wood SP-WPC, respectively. Sample compositions are flour was dyed with CI Reactive Red 281 of presented in Table 2. Extrudate were pelletized into 1%o.w.f. at liquor ratio 4:1 using Sodium carbonate pellets and injection molded into tensile and flexural and Sodium chloride to increase dye affinity. specimens using an injection molding machine with Caesalpinia sappan bark was grinded into small nozzle temperature of 180°C and mold temperature of 40 ° C. pieces and boiled in water (1:10 weight ratio, 80°C, 4 hrs) to receive dye solution (red). Delignin wood flour was dyed with dye solution using Aluminium 2.4 Characterization and testing sulphate 1.5%o.w.f. to improve dye affinity. Fiber integrity in all composites was characterized In all dyeing process, delignin wood flour was dyed by Fourier transform infrared spectrophotometer with upper 60% absorption ratio of the origin natural (FTIR) and Thermogravimetric analyzer (TGA). dye solution, which concentrations of dye solution FTIR spectra of sample were recorded on a Vertex before and after dyeing process were determined 70, BRUKER in range 4,000-400 cm -1 using KBr using a UV/VIS Spectrophotometer (PG Instruments disc. Spectra were obtained using 32 scan and a Ltd.). resolution 4 cm -1 . TGA measurements were analyzed using TGA/DSC1 STAR System, Mettler Table 2. Sample codes and their compositions. Toledo. Temperature program for tests were run Sample Compositions Compositions from 40°C to 700°C at heating rate 10°C/min in Code ratio nitrogen atmosphere (20 ml/min). Tensile test was performed according to ASTM D- HDPE HDPE 100 638-03 using LR 50 K universal testing machine MA-HDPE HDPE : MAPE 100 : 15 (Lloyd Instrument) equipped with 50 kN load cell W-WPC HDPE : Original wood 40 : 60 : 6 and a crosshead speed of 5 mm/min. Ten : MAPE measurements of each sample code were conducted D-WPC HDPE : Delignin 40 : 60 : 6 to calculate the average and its standard deviation. wood : MAPE Flexural test was performed according to ASTM D- DR-WPC HDPE : Direct dyed 40 : 60 : 6 wood : MAPE 790-03 using LR 50 K universal testing machine RT-WPC HDPE : Reactive dyed 40 : 60 : 6 (Lloyd Instrument) equipped with 50 kN load cell. wood : MAPE Specimens were deflected in three-point loading SP-WPC HDPE : Sappan dyed 40 : 60 : 6 mode until failure or until 5 percent strain was wood : MAPE reached in the outer surface of test specimen with a crosshead speed of 1.8 mm/min. 2.3 Preparation of wood-plastic composite (WPC) Morphology of composites was studied from their fracture surface by means of scanning electron Before compounding, wood flour were dried in an microscopy (JSM 5410 LV). Samples were prepared air-circulating oven at 80°C for 24 hours. by immersing specimen in liquid nitrogen and then Composites were prepared by compounding HDPE breaking them. The fractured surfaces were sputter- 40 wt% and wood 60 wt% with MAPE (6 wt% of coated with gold for observation. fibers) as coupling agent in a twin screw extruder
3 Results and 3 d discussion n 3 3.1 Content o of lignin After Chlorite A e treatment, Klason ligni in was remov ved about 70 wt% a % of original lignin conte ent. In Fig.1, the re eduction of lignin in wo ood flour wa as confirmed by FTIR showin F ng disappear rance of the e characteris stic cm -1 peaks of lign p nin at wave n number of 1, ,600-1,500 c which is arom w matic skeleto on vibration [ [2]. Fig.2. Lignin F n index of wo ood and mod dified wood. Direct-dyed d Reacti ive dyed Sappan dyed Or riginal wood Delignin-w wood Fig. 1. FTIR spec ctra of origin nal and modified w wood fibers. Fig. 2 indica F ates normali ized FTIR p peaks of lig gnin Fig 3. Color r of wood and d modified w wood fibers. (L Lignin inde ex), which was calcula ated using the fo following equ uation: De elignin wood d flour had significantly y lighter colo or com mpared to original ru ubber wood flour. Aft er I 1507 × = I dy yeing, synthe etic dyed wo ood flour w was bright re ed 00 ( (1) L ignin index x 10 wh hile Sappan dyed one w was dark re ed as seen i in 1738 Fig g.3. w where I is a p peak intensity y of FTIR sp pectra. The pe eak 1,507 cm -1 in ntensities at of lignin w were normaliz zed 38 cm -1 of with the pe w eak at 1,73 f hemicellu uose (u unconjugated d C=O) [3]. This peak w was chosen a as a re eference pe eak because it slightly changed af fter tr reatment wit th acid or dy yes. It is see en that lignin n in m modified woo od flour were e in the same e range. 3
Recommend
More recommend
