Swelling properties of chemically modified oil palm empty fruit bunch based polyurethane composites

In this study, the diffusion of various types of solvent in oil palm empty fruit bunch/polyurethane composites, produced from chemically modified empty fruit bunches, was investigated. The solubility parameters and polymer–solvent interaction parameters of the produced composites were determined. The void contents of the composites were also determined before swelling tests to eliminate the free solvent present in the system. From the results obtained, we found that the diffusion of the solvents was dependent on the compatible group available and the voids present in the system. The solubility parameters of the empty fruit bunch/polyurethane composites with different degrees of chemical modification were 11.6 and 11.7 (cal/cm^?3)^1/2. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

The effect of compounding techniques on the mechanical properties of oil palm empty fruit bunch–polypropylene composites

Oil palm empty fruit bunch–polypropylene (EFB–PP) composites were produced by employing 2 types of compounding techniques, that is, an internal mixer and a single-screw extruder. The mechanical and water absorption properties of both types of composites were investigated. Overall, for both types of composites, the incorporation of the EFB into PP matrix has resulted in the improvement in the tensile modulus. However, the tensile strength, elongation at break, and impact strength decreased with increasing filler loading. Poor filler–matrix interaction or compatibility and, also, the size irregularity of the EFB are believed to be responsible for the poor ultimate performance. Composites produced by an internal mixer (IM) have displayed higher tensile strength, tensile modulus, and impact strength than with those produced by extrusion (EX). The better performance has been attributed to the effectiveness of the IM, which produces better compounding and improves the wetting of the filler surface. Incorporation of compatibilizer and coupling agent, that is, Epolene wax (E-43) and 3-Aminopropyl triethoxysilane (3-APE), respectively, have produced composites with improved tensile strength for both EX and IM composites. In addition, both types of treatment have resulted in an increase in tensile modulus of EX composites and impact strength of IM composites. Water absorption tests have revealed that the presence of coupling agents and compatibilizers have affected the amount of water absorbed, especially for the 3-APE-treated EFB–PP composites. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 70: 2647–2655, 1998     

Polyurethane composites based on oil palm empty fruit bunches: Effect of isocyanate/hydroxyl ratio and chemical modification of empty fruit bunches with toluene diisocyanate and hexamethylene diisocyanate on mechanical properties

This study focuses on the effect of isocyanate (NCO)/hydroxyl (OH) group ratios and chemical modification of oil palm empty fruit bunches (EFBs) with toluene diisocyanate (TDI) and hexamethylene diisocyanate (HMDI) on the mechanical properties of EFB–polyurethane (PU) composites. The tensile, flexural, and impact properties are affected by the NCO/OH ratios. The tensile strengths, flexural strengths, and toughness increase as the NCO/OH increases; however, the modulus decreases. The reduction in the modulus is attributable to the increased flexibility of the PU linkages. Chemical modification of the EFBs increases the tensile strength, flexural strength, and toughness; however, the modulus is lowered as the percentage of treated EFB is increased. Impact strength results show that the strength increases as the NCO/OH ratio is increased. At NCO/OH ratios of 1.0 and 1.1, the composites with HMDI‐treated fibers exhibit higher impact strength than those with TDI‐treated and untreated fibers, respectively. This may be due to the longer and more flexible chain length of HMDI as compared to TDI, which enables the composites to absorb more energy before failure. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

The effect of coupling agents on the mechanical and physical properties of oil palm empty fruit bunch–polypropylene composites

Oil palm empty fruit bunch–polypropylene (EFB‐PP) composites have been produced using a twin‐screw extruder as the compounding equipment. Two levels of EFB were employed, 40 % and 60 % of the total weight of the sample. Three types of coupling agent, maleic anhydride‐modified polypropylene (commercial name Epolene E‐43), polymethylene(polyphenyl isocyanate) (PMPPIC) and 3‐(trimethoxysilyl)‐propylmethacrylate (TPM), were used. Overall, all coupling agents imparted considerable improvements in the flexural properties, E‐43 showing the highest enhancement. However, only E‐43 was observed to improve impact strength and tensile properties of the composites. All composites with coupling agents showed lower water absorption and thickness swelling. The absorption and swelling decreased as the loading of the coupling agents was increased. © 2000 Society of Chemical Industry     

湿固化作用对NCO／OH型双组分聚氨酯涂料漆膜性能的贡献

NCO/OH型聚氨酯漆的固化机制是—NCO与—OH反应交联和—NCO与空气中水分反应交联的叠加。通过同一种NCO/OH聚氨酯漆的漆膜在相同温度而湿度悬殊的环境中固化过程中漆膜性能增长情况的对比,证实了湿固化对漆膜的充分固化与漆膜性能的增长有明显的贡献。     

Effect of the NCO/OH ratio on the properties of Mesua Ferrea L. seed oil‐modified polyurethane resins

A series of polyurethane resins with varying NCO/OH ratios (0.8–2.0) has been synthesized from the monoglyceride of Mesua Ferrea L. seed oil, poly(ethylene glycol) (M_n, 200 g mol^?1) and 2,4‐toluene diisocyanate in the presence of dibutyl tin dilaurate as the catalyst. The effects of the NCO/OH ratios of the synthesized resins on the physical properties, such as hydroxy values, acid values, saponification values, iodine values, specific gravities and isocyanate values have been studied. The formation of the polyurethane resins was confirmed by viscosity measurements, and FTIR, UV and ¹H NMR spectroscopic studies. Performance characteristics, such as impact resistance, flexibility, gloss, hardness, adhesive strength and chemical resistance, of the cured resins were investigated as a function of the varying NCO/OH ratios, with an influence of these ratios being observed for most of the above properties. Thermogravimetric analysis (TGA) demonstrated that the thermal stabilities of the cured resins increased with an increase in the NCO/OH ratios. The amounts of char residues at 550 °C were also found to be greater for higher NCO/OH ratios of the oil‐modified polyurethane resins. Copyright © 2005 Society of Chemical Industry     

Acoustical,thermal, and morphological properties of zein reinforced oil palm empty fruit bunch fiber bio‐composites

In this research, biodegradable composites were prepared with zein as a polymer matrix and oil palm empty fruit bunch (OPEFB) as fiber reinforcement. The fibers were treated with sodium hydroxide (NaOH). The effects of sodium hydroxide treatment on sound absorption, thermal stability, and fiber‐polymer matrix interaction in composites were examined. The acoustical sound absorption coefficients of the composites were evaluated using two‐microphone transfer function impedance tube method. The spectral, thermal, and morphological studies of the composites were analyzed and characterized using scanning electron microscope (SEM), thermogravimetric analysis (TGA), and Fourier transform infrared (FTIR) spectroscopy. It was found that in all the biodegradable composites, the sound absorption coefficients increased as the frequency increased. Increases in fiber loading caused sound absorption coefficients of the composites to increase. The sodium hydroxide treatment showed a better interface adhesion on fiber and zein matrix. It was also found that this treatment increased the sound absorption coefficients. This was supported by qualitative analysis on the SEM micrographs and FTIR spectrum. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 44164.     

Wood‐based composites with thermoplastic polyurethane as matrix polymer

This research reports the influence of the mechanical properties of thermoplastic polyurethane (TPU) as a function of wood filler percentage. Wood flour was mixed with two different chemically based TPUs. Also, moisture content during compounding process as well as the origin of moisture (wood or TPU) were studied. All experimental designs and statistical analysis were done with the software Design Expert Version 10. Composite preparation took place in a multi‐stage process. The results showed that 70% wood filler can be incorporated in the composite manufacture. The properties of the composite were mainly influenced by the proportion of wood and TPU. Wood flour increased the density, hardness, water absorption, and tensile modulus with a decrease in impact resistance and abrasion resistance of the composite. Tensile strength exhibited a decrease up to ～35% wood content, but an increase with further addition of wood. Moisture content had only a minor influence on the mechanical and water absorption properties despite the noted severe moisture sensitivity of TPU, which usually leads to decline in mechanical properties. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46344.     

The effect of various anhydride modifications on mechanical properties and water absorption of oil palm empty fruit bunches reinforced polyester composites

The chemical modification of oil palm empty fruit bunches (EFB) using non‐catalysed reaction with acetic, propionic and succinic anhydrides were investigated. Proof of modification was indicated by the increase of weight and was confirmed by Fourier‐transform infrared analysis (FT‐IR). The mechanical and water‐absorption properties of all anhydride‐modified EFB composites were evaluated at different volume fractions (V_f). The properties were improved for these modified fibres, whereas unmodified EFB fibres exhibited poor mechanical properties and higher water absorption. Acetic anhydride modification showed the greatest benefit on composite properties, followed by propionic and succinic anhydride modification. © 2001 Society of Chemical Industry     

Structure and properties of polyurethane/nanosilica composites

Nanosilica particles were directly introduced into polyester polyol resins through in situ polymerization and blending methods, then cured by isophorone diisocyanate (IPDI) trimers to obtain nanocomposite polyurethanes. FTIR and TGA analyses indicated that more polyester segments had reacted with silica particles during in situ polymerization than during the blending method, accompanied by higher T_g and more homogeneous dispersion of nanosilica particles in the polymer matrix from in situ polymerization. Maximum values in T_g, tensile properties, macrohardness, abrasion resistance, and UV absorbance were obtained when the particle size of silica was about 28 nm. The polyurethane/nanosilica composites obtained by in situ polymerization generally had better mechanical properties than those by the blending method except for some unexpected macrohardness at relatively high silica content. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 95: 1032–1039, 2005     

Modification of oil palm empty fruit bunches with maleic anhydride: The effect on the tensile and dimensional stability properties of empty fruit bunch/polypropylene composites

Oil palm empty fruit bunch (EFB)‐filled polypropylene (PP) composites were produced. The EFB filler was chemically modified with maleic anhydride (MAH). The effects of the filler size and chemical modification of EFBs on the tensile and dimensional stability properties of EFB–PP composites were studied. The composites with MAH‐treated EFBs showed higher tensile strengths than those with untreated EFBs. This was attributed to the enhanced compatibility between the MAH‐treated EFBs and PP matrix, as shown in a scanning electron microscopy study. Fourier transform infrared analysis showed evidence of C?C and C?O bonds from MAH at 1630 and 1730 cm^?1, respectively. The MAH‐treated PP composites showed lower water absorption and thickness swelling than those with untreated EFBs. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 827–835, 2003     

Thermal and mechanical properties of injection moulded heat-treated oil palm empty fruit bunch fibre-reinforced high-density polyethylene composites

ABSTRACT

Oil palm empty fruit bunch (OPEFB) was heat treated at 180°C using a vacuum oven for one hour, extruded and compounded with high-density polyethylene at 10%, 20% and 30% weight fraction. The composites then were injection moulded into dumb-bell shaped specimens. The effect of composition and heat treatment on the thermal properties of composites were investigated using Thermogravimetric Analysis (TGA) and Differential Scanning Calorimetry (DSC). The tensile and flexural properties were also tested using an Instron Universal Testing Machine. TGA shows an increase in the degradation peak temperature of the heat-treated composites. DSC revealed an increasing trend in the degree of crystallinity (X_c) of the matrix as the heat-treated empty fruit bunch was used as a filler. An increment in the tensile modulus and tensile strain were observed for the treated fibre composites. In addition, the tensile strength value was increased for treated fibre composites with lower fibre loading.     

Optimization of thermoelectric properties of metal‐oxide‐based polymer composites

Thermoelectric modules can be used for thermal energy harvesting. Common rigid thermoelectric stacks usually contain heavy metal alloys such as Bi₂Te₃. In order to substitute conventional materials and to reduce manufacturing costs, nontoxic, inexpensive and abundant materials using low‐cost processes are first choice. This study deals with polymer composites consisting of a polysiloxane matrix filled with thermoelectric Sn_0.85Sb_0.15O₂ particles in micrometer scale. Thin composite sheets have been prepared by doctor blade technique and the Seebeck coefficient, the electrical and thermal conductivity, and the porosity were measured. Platelet‐type particles, consisting of Sn_0.85Sb_0.15O₂‐coated insulating mica substrate and globular Sn_0.85Sb_0.15O₂ particles have been varied in size, coating thickness and were mixed with each other in different ratios. The filler content was varied in order to maximize the figure of merit, ZT, to 1.9 × 10^?5 ± 4 × 10^?6. Owing to their low raw material costs and the high degree of design freedom of polymer composites, one may use these materials in thermoelectric generators for remote low‐power demanding applications. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2014 , 131, 40038.     

初始NCO/OH摩尔比对直接乳化法制备水性聚氨酯的影响

以异佛尔酮二异氰酸酯(IPDI)、聚醚二元醇(PPG-210)、二羟甲基丙酸(DMPA)等为主要原料,采用直接乳化法合成了一系列水性聚氨酯(WPU)乳液;通过傅立叶变换红外光谱分析、差示扫描量热分析、粒径分析及力学性能测试等,研究了WPU乳液粒径大小、分子链结构、力学性能和热性能,并探讨了初始NCO/OH摩尔比(nNCO/nOH)对胶膜性能的影响。结果表明,随着初始nNCO/nOH比值的增大,所得乳液的稳定性变差,粒径变大,胶膜的拉伸强度先变大后降低,断裂伸长率逐渐降低;其相应的热分解温度稍有降低。     

The influence of the NCO/OH ratio and the 1,6-hexanediol/ dimethylol propionic acid molar ratio on the properties of waterborne polyurethane dispersions based on 1,5-pentamethylene diisocyanate

1,5-Pentamethylene diisocyanate, a novel aliphatic diisocyanate formed from bio-based 1,5-pentamethylenediamine, has been used as a hard segmented material to synthesize polyurethane. In this study, several waterborne polyurethane (WPU) dispersions have been successfully prepared by a prepolymer process from 1,5-pentamethylene diisocyanate poly(polyether) with different NCO/OH ratios and 1,6-hexanediol (HDO)/dimethylol propionic acid (DMPA) molar ratios. The Fourier transfonn infrared (FTIR) spectra, thermogravimetric analysis, differential scanning calorimetry, X-ray diffiraction, and a mechanical tensile test were used to investigate the structures, thermal stability, phase separation, crystallinity, mechanical properties, and adhesive performance of the WPU dispersions. The FTIR results indicate that the degree of hydrogen bonding and the numbers of urea groups increase as the NCO/OH ratio and HDO/DMPA molar ratio increase. Furthermore, the phase separation increases and the thermal stability decreases as the NCO/OH ratio increases or the HDO/DMPA molar ratio decreases. Finally, WPU3.0-2.4 (NCO/OH = 3, HDO/DMPA = 2.4) exhibits a maximum tensile strength and shear strength, pointing to its possible use as an adhesive. These results could provide a very valuable reference for industrial applications of WPU.     

Effects of NCO/OH Ratio and Reactive Diluent Type on the Adhesion Strength of Polyurethane Methacrylates for Cord/Rubber Composites

A series of dual curable polyurethane methacrylate-based oligomers were synthesized by changing the NCO:OH ratio and then were included in adhesive formulations using trimethylolpropane trimethacrylate and tricyclodecane dimethanol diacrylate (TCDDA) as reactive diluents. The effects of NCO:OH ratio and reactive diluent type on the structural properties of UV-cured free films and adhesion properties between polyester cord/rubber surfaces were studied. The highest adhesion strength of the 103?N?cm^?1 was obtained when the NCO:OH ratio was set as 4 and the TCDDA was used as a reactive diluent.     

Jute‐fiber‐reinforced polyurethane green composites based on Mesua ferrea L. seed oil

Two types of environmentally friendly jute‐fiber‐reinforced green composites based on Mesua ferrea L. were prepared with poly(urethane ester) and poly(urethane amide) resin blends with commercially available partially butylated melamine–formaldehyde and epoxy resins through solution impregnation and hot‐curing methods. The composites were cured at a temperature of about 130–140°C under a pressure of 35 ± 5 kg/cm² for about 2 h. The mechanical properties, such as tensile strength, flexural strength, elongation at break, hardness, and density, of all of the composites were measured and compared. The mode of interaction between the filler and the matrix were studied by Fourier transform infrared spectroscopy and scanning electron microscopy of the fractured composite samples. The water uptake in different chemical media was observed, and we found that all of the composites possessed excellent hydrolytic stability against almost all of the media except the alkali. Thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) were used to analyze the thermal behavior of the composites. TGA of the composites showed degradation much above that of the virgin blends, which indicated their high thermostability. The glass‐transition temperatures, as shown by DSC analysis, were found to be much higher. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Flame‐retardant and mechanical properties of rigid polyurethane foam/MRP/mg(OH)2/GF/HGB composites

Some rigid polyurethane foam (RPUF) composites modified with microencapsulated red phosphorus (MRP), magnesium hydrate (Mg(OH)₂), glass fiber (GF), and hollow glass bead (HGB) were prepared. The influence of the MRP, Mg(OH)₂, GF, and HGB on the flame‐retardant, combustion, and mechanical properties of the filled RPUF composites was investigated. The results showed that the flame‐retardant and the combustion properties of the composites were obviously improved, the limiting oxygen index, half burning time and the residual mass/original mass ratio increased with increasing MRP/Mg(OH)₂ weight fraction, especially in case of MRP/Mg(OH)₂ weight fraction of 8 wt %; the carbon monoxide (CO) concentration decreased with increasing MRP/Mg(OH)₂ weight fraction, When the composites were loaded appreciate content of the HGB and the GF, the maximum torque and compressive strength of the composites were improved. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46551.     

Synthesis of polyurethane acrylates by hydrogenated castor oil and dimer‐based polyester diol and study on pressure‐sensitive adhesive

Synthesis of polyurethane acrylate (PUA) and preparation of the UV‐cured pressure‐sensitive adhesives (PSA) are reported. Molecular weight (M_w) (by gel permeation chromatography) and viscosity (η*) of PUA were measured. Characterization of PUA and PSA before and after UV‐curing was made by FTIR. Increase of the hydroxyls from hydrogenated castor oil/hydroxyls from dimer‐based polyester diol (OH_HCO/OH_Diol) ratio decreased the M_w and η* value of PUA. Dynamic viscoelastic properties (by dynamic rheological spectrometer) and performance of the UV‐cured PSA were also studied. Increase of the OH_HCO/OH_Diol ratio increased the storage modulus (G′), the loss modulus (G″), and complex viscosity (Eta*) of the UV‐cured PSA, which, in turn, enhanced holding power and shear adhesion failure temperature (SAFT) and yet decreased peeling strength. Substitution of OB for DBTDL depressed the M_w and η* value of PUA, while the G″ and Eta* values of the UV‐cured PSA were elevated, which, in turn, increased the holding power and SAFT and yet depressed the peeling strength. Elevation of the tackifying resin content depressed the G′, G″, and Eta* values of the cured PSA and yet increased glass transition temperatures (T_g) of PSA, measured by differential scanning calorimetry. Peeling strength of PSA elevated as increasing the tackifying resin, while the holding power and SAFT fell. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 1814–1821, 2005     

Effects of fiber‐surface treatment on the properties of hybrid composites prepared from oil palm empty fruit bunch fibers,glass fibers,and recycled polypropylene

In this article, we report the effects of hybridization and fiber‐surface modification on the properties of hybrid composites prepared from recycled polypropylene (RPP), coupling agents, oil palm empty fruit bunch (EFB), and glass fibers through a twin‐screw extruder and an injection‐molding machine. The surface of the EFB fibers was modified with different concentrations (10–15 wt %) and temperatures (60–90°C) of alkali solutions. The structure and morphology of the fibers were observed with the help of Fourier transform infrared spectroscopy and scanning electron microscopy. Different types of composites were fabricated with untreated, alkali‐treated, and heat‐alkali‐treated fibers. Comparative analysis of the mechanical, structural, morphological, and thermal properties of the composites was carried out to reveal the effects of treatment and hybridization. The analysis results reveal that composites prepared from the alkali‐treated (in the presence of heat) fibers show improved mechanical, thermal, and morphological properties with a remarkably reduced water absorption. Additionally, the crystallinity of RPP also increased with the development of biaxial crystals. The improvement of various properties in relation to the structures and morphologies of the composites is discussed. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43049.