Preparation of flame‐retardant leather pretreated with pyrovatex CP

Resistance to burning is one of the most useful properties that can be imparted to leather. Pyrovatex CP is rich in phosphorus and nitrogen and has been successfully used as a flame‐retardant agent in the presence of etherified methylolated melamine (EMM). The effects of a finishing formulation containing Pyrovatex CP and EMM on the flame retardancy and other properties of modified leather have been studied under different conditions. The synergistic effect of the N/P ratio has been thoroughly investigated through the estimation of the nitrogen and phosphorus contents, and their impact on the flame retardancy, tensile strength, and elongation at break of the treated leather has been studied. An investigation of the different factors has led to the following conclusions: (1) the P and N percentages increase with increasing curing temperature and time, (2) increases in the Pyrovatex CP and EMM concentrations are accompanied by an enhancement of the P and N percentages, and (3) all samples exhibit loss in their tensile properties but within an acceptable range (20%). © 2005 Wiley Periodicals, Inc. J Appl Polym Sci, 2006     

Effect of trace chloride on the char formation and flame retardancy of the LLDPE filled with NiAl‐layered double hydroxides

Layered double hydroxides (LDHs) have received intensive attentions for the potential as flame retardants of polyolefin. In the work, trace amounts of chloride were investigated for their synergistic effects on the char formation and flame retardancy of the linear low‐density polyethylene (LLDPE) filled with NiAl‐LDHs. Results showed that 0.5 wt% of NH₄Cl incorporation enabled the char yield of 20%LDH/LLDPE (20 wt% of NiAl‐LDH) increase from 10.4% to 49.6%. Other chlorides likewise offered significant increase in the char yield of 20%LDH/LLDPE. With the flame‐retardant measurements of cone calorimeter and limiting oxygen index device, it is revealed that the flame retardancy of LLDPE filled with NiAl‐LDHs could be greatly improved when trace amounts of NH₄Cl were further introduced. Thermal stability analysis illustrated that the presence of NiAl‐LDHs or NH₄Cl all had positive effects on the thermal stability of LLDPE, in which the chlorides influenced the LLDPE thermal stability via direct participation in the degradation of LLDPE. The synergetic mechanism analysis reveals that the introduction of chloride enabled the LLDPE decomposed products have more tendency to grow carbon nanotubes with the presence of NiAl‐LDH catalysts. Finally, the mechanical properties of LLDPE filled with NiAl‐LDHs and NH₄Cl were also investigated.     

Application of chlorinated waste rubber as a flame retardant of low density polyethylene

For the reuse of the abundant waste rubber (WR), chlorinated waste rubber (Cl‐WR) was prepared by a water‐based chlorination method using chlorine gas as the chlorinating reagent. The resultant Cl‐WR was used as a flame retardant of low density polyethylene (LDPE) matrix. The properties of WR and Cl‐WR were characterized by thermogravimetric (TG) and Fourier transform infrared (FTIR) spectrometer. The results indicated that the Cl‐WR with a 42% chlorine content had a higher char residue than WR. The limiting oxygen index (LOI) value can be increased up to 27.2 and the flame retardancy reached to the maximum (V‐0) grade for the LDPE/Cl‐WR‐Sb blends with mass ratios of Cl‐WR/LDPE and Cl‐WR/Sb₂O₃ being 80/100 and 1.5/1, respectively. The improvement of the flame retardancy and thermal properties of the LDPE/Cl‐WR‐Sb blends were attributed to the char formation and synergistic effect between Cl‐WR and Sb₂O₃ in a high temperature region, although the mechanical properties of the said blend decreased in comparison with that of the neat LDPE. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Polydopamine modified ammonium polyphosphate modified shape memory water-borne epoxy composites with photo-responsive flame retardant property

Shape memory epoxy (SMEP) is a high performance shape memory polymer; however, is extremely flammable which severely restricts its applications. In this work, a novel polydopamine modified ammonium polyphosphate (PDA@APP) flame retardant was prepared to improve the flame retardant and enrich the response method of SMEP. Through flame retardancy test confirmed that the flame retarding properties of the PDA@APP/WEP composites significantly improved than the APP/WEP composites, the limiting oxygen index (LOI) values of the APP/SMEP and the PDA@APP/SMEP samples increased by 29.8% and 32.2%, respectively. Moreover, the PDA@APP/WEP composites had excellent light response shape-memory performance. Interestingly, the PDA@APP/WEP treated polyester fabric exhibited excellent light crease recovery performance and excellent flame retardant property. This work develops a new method for fabric crease recovery and will help broaden the application of WEP and its composites.     

Easy-care properties of simultaneously grafted and crosslinked cotton fabrics

The Concurrent grafting of acrylic acid (AA) and crosslinking of dimethylodihydroxyethyleneurea (DMDHEU) with cotton fabric in the presence of ammonium persulfate [(NH₄)₂S₂O₈)], magnesium chloride hexahydrate (MgCl₂ · 6H₂O), and ammonium chloride (NH₄Cl) catalysts were studied. These salts were separately used or as a binary mixture of (NH₄)₂S₂O₈/MgCl₂ · 6H₂O or (NH₄)₂S₂O₈/NH₄Cl. The pad–dry–cure method was employed for the fabric treatment under a variety of conditions. The latter include the nature and kind of the single catalyst as well as pair-mixed catalysts, the concentrations of the catalyst and AA, and temperature and duration of curing. The effects of these conditions on the values of the carboxyl content and crease recovery angle (CRA) of the treated fabrics were evaluted. The tensile strength, elongation at break, dyeability, aqueous and nonaqueous oily soiling, and soil-release properties of the treated fabrics were also examined. Results obtained indicated that all treated fabrics have superior properties, except tensile strength and elongation at break, as compared with the untreated fabric (control). However, beside the AA-grafting and DMDHEU-crosslinking reactions, there are other types of reactions catalyzed by the salts used, viz., the addition reactions between AA molecules and the cellulosic hydroxyls The tentative mechanisms for these reactions are suggested. © 1996 John Wiley & Sons, Inc.     

Study of Fire Retardancy and Thermal and Mechanical Properties of HDPE-Wood Composites

This article reports a study of flame retardancy and thermal and mechanical properties of wood-plastic composites (WPCs) based on high-density polyethylene and pine flour. The study shows that sample composition plays an important role in WPCs' properties. The influence of additives like fillers (SiO₂ or CaCO₃) and flame retardants ammonium polyphosphate (APP) and pentaerythritol (PER) on WPCs' properties has been considered. The best properties are shown in samples using SiO₂ as filler and treated with the intumescent fire retardant APP/PER. Such samples have excellent fire retardancy with V-0 rating (UL-94 test) and imply that APP/PER fire retardant ensures effective fire retardancy for WPCs.     

Synthesis and properties of a phosphate ester as curing agent in an epoxy resin system

Phosphate ester compounds display good flame retardancy effect in epoxy resin systems. In this paper, several novel phosphate esters, used as curing agents for epoxy resins, were synthesized based on P₂O₅, phosphoric acid, and different types of alcohol. The structures of phosphate esters were characterized by ³¹P nuclear magnetic resonance (³¹P NMR). Then, a series of flame retardant epoxy composites were prepared by curing the epoxy resins (E-44) with the phosphate esters. The flame retardancy and thermal degradation behaviors of flame retardant epoxy composites were investigated by cone calorimeter test (CCT) and thermogravimetric analysis (TGA), respectively. The results of CCT indicated that phosphate esters can significantly decrease heat release rate, total heat release (THR), and smoke production rate. The sample cured by butyl phosphate ester from phosphorus pentoxide, phosphoric acid and butanol showed the best flame retardant performance among all samples. The TGA results showed that phosphate esters could enhance char residues of flame retardant epoxy composites when compared with those of a composite using T31 as a curing agent at high temperature. It may be concluded that good flame retardant properties of flame retardant epoxy composites are related to the formation of a protective phosphorus-rich char layer. These phosphate esters have a good future on flame retardant epoxy composites.     

Study on char reinforcing of different inorganic fillers for expandable fire resistance silicone rubber

Sodium silicate monohydrate (NSH), glass frits (GF) and aluminum hydroxide (ATH) were incorporated into room temperature vulcanized (RTV) silicone rubber (SR) as char reinforcing materials to improve the fire resistance of intumescent flame retardant silicone rubber. SR composites containing only intumescent flame retardant such as phosphorus nitrogen composite flame retardant (NH₂-C) and expandable graphite (EG) were used as comparison samples. Limiting oxygen index (LOI) test, vertical burning test (UL-94), flame resistance test, scanning electron microscopy (SEM) and X-ray diffraction spectroscopy tests, as well as volume variation and compression strength of char residues were used to discuss the effects of the above-mentioned fillers on the fire resistance, char residue strength and char integrity of SR composites. The results showed that SR composite filled with only intumescent flame retardants EG and NH₂-C had excellent flame retardancy. After adding ATH, the char residue was relatively dense and had good compressive strength, but its thermal insulation performance was reduced. GF or NSH reduced the flame retardancy of SR composites, but it obviously played a role in binding combustion residues, forming new crystals and improving the stability of char residues.     

Using Persulfate Oxidized Chitosan as a Novel Additives in Easy-Care Finishing for Cotton Textiles

Easy care finishing of cotton fabric using glyoxal in the presence and absence of low molecular weight chitosan, i.e., persulfate-oxidized chitosan, as a novel additive along with MgCl₂·6H₂O as an acid catalyst was studied in detail. Major factors affecting finishing reaction were studied with respect to glyoxal, oxidized chitosan, and catalyst concentrations in addition to curing time and temperature of treatment according to the pad-dry-cure method. The obtained results show the following findings: (a) increasing the glyoxal concentration from 5–50 g/l in absence of oxidized chitosan is accompanied by an increase in crease recovery angle and a decrease in tensile strength of the finished fabric, whereas that treated in the presence of oxidized chitosan shows a higher tensile strength and to some extent comparable crease recovery angle with respect to that finished in the absence of it when the concentration of glyoxal increases; (b) increasing the oxidized chitosan concentration is accompanied by decreasing crease recovery angle, whereas the tensile strength increases when glyoxal concentration increases within the range studied; (c) increasing the MgCl₂·6H₂O from 0–15 g/l is accompanied by an increase in the crease recovery angle and a decrease in tensile strength of the finished fabrics in the presence and absence of oxidized chitosan; (d) increasing the time and temperature of curing of the finished fabrics is accompanied by an increase in crease recovery angles and decreases in tensile strength; and (e) the dry wrinkle recovery angle of cotton fabric samples finished in presence of O-chitosan is decreased after washing, and the higher the washing cycle the lower the dry wrinkle recovery angle.     

The influence of ammonium and methods for removal during the anaerobic treatment of poultry manure

The addition of exogenous NH₄Cl to poultry manure and synthetic medium was used to study the effect of ammonia-nitrogen on the activity and composition of a methanogenic consortium. Results indicated that the production of biogas and methane was not affected by the variation in NH₄Cl concentration within the range 2–10 g dm⁻³ (0·5–2·6 g N-NH₄ dm⁻³). At higher values of ammonium (10–30 g dm⁻³ or 2–8 g N-NH₄ dm⁻³) a significant decline in both parameters (by 50–60% for biogas and 80–90% for methane) was observed. A significant decrease in the numbers of bacteria of all physiological groups (especially proteolytic and methanogenic) was observed when more than 30 g NH₄Cl dm⁻³ (7·8 g N-NH₄ dm⁻³) was added to the fermentation medium. The addition of 10% (w/v) of powdered phosphorite ore enhanced the production of biogas and methane at NH₄Cl concentrations up to 30 g dm⁻³, and also changed the composition of the methanogenic consortium. A partial recovery in the numbers of proteolytic and methanogenic bacteria coupled with the decrease in the density of sulphate-reducers was observed. High concentrations (more than 50 g dm⁻³) of NH₄Cl seemed to cause irreversible inhibition of methanogenesis which could not be eliminated by the addition of phosphorites. ©1997 SCI     

Flammability properties of paper coated with poly (methylenephosphine), an organophosphorus polymer

The flame retardant properties of paper coated with either poly(methylenephosphine) ( PMP ) or poly(methylenephosphine oxide) ( PMP‐O ) are evaluated. Paper sheets made from thermomechanical pulp were coated with PMP (M_n = 27,000 g mol^?1, polydispersity index (PDI) = 1.47), PMP‐O (M_n = 30,000 g mol^?1, PDI = 1.24), or monobasic ammonium phosphate (MAP) to achieve an approximate loading of 0.8 mmol P/g paper. Thermal stability studies by thermogravimetric analysis show that the paper degrades in two main stages, with the second thermo‐oxidative stage having a slower rate of degradation for paper treated with flame retardants. The flame retardancy of the sheets was evaluated by Technical Association of Pulp and Paper Industry Standard Method T461 cm‐00 and by limiting oxygen index (LOI) according to ASTM D2863. After leaching with water, samples coated with PMP or PMP‐O show no loss of flame retardancy, while those coated with MAP lose all flame retardancy. The LOI of paper coated with PMP (23.1%) or PMP‐O (25.9%) is higher than those of uncoated paper (19.6%), but lower than MAP‐coated paper (34.7%). Analysis of the char provided evidence that the flame retardant mechanism of PMP and PMP‐O involves the formation of phosphorus oxides and acids. Copyright © 2014 John Wiley & Sons, Ltd.     

Novel phosphorus‐containing hardeners with tailored chemical structures for epoxy resins: Synthesis and cured resin properties

A comparative evaluation of systematically tailored chemical structures of various phosphorus‐containing aminic hardeners for epoxy resins was carried out. In particular, the effect of the oxidation state of the phosphorus in the hardener molecule on the curing behavior, the mechanical, thermomechanical, and hot‐wet properties of a cured bifunctional bisphenol‐A based thermoset is discussed. Particular attention is paid to the comparative pyrolysis of neat cured epoxy resins containing phosphine oxide, phosphinate, phosphonate, and phosphate (with a phosphorus content of about 2.6 wt %) and of the fire behavior of their corresponding carbon fiber‐reinforced composites. Comparatively faster curing thermosetting system with an enhanced flame retardancy and adequate processing behavior can be formulated by taking advantage of the higher reactivity of the phosphorus‐modified hardeners. For example, a combination of the high reactivity and of induced secondary crosslinking reactions leads to a comparatively high T_g when curing the epoxy using a substoichiometric amount of the phosphinate‐based hardener. The overall mechanical performance of the materials cured with the phosphorus‐containing hardeners is comparable to that of a 4,4′‐DDS‐cured reference system. While the various phosphorus‐containing hardeners in general provide the epoxy‐based matrix with enhanced flame retardancy properties, it is the flame inhibition in the gas phase especially that determines the improvement in fire retardancy of carbon fiber‐reinforced composites. In summary, the present study provides an important contribution towards developing a better understanding of the potential use of such phosphorus‐containing compounds to provide the composite matrix with sufficient flame retardancy while simultaneously maintaining its overall mechanical performance on a suitable level. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Curing characteristics of urea–formaldehyde resin in the presence of various amounts of wood extracts and catalysts

The characteristics of urea–formaldehyde (UF) resin curing in the presence of wood extracts and a catalyst [ammonium chloride (NH₄Cl)] were investigated by differential scanning calorimetry (DSC). The effects of extracts from 16 wood species on resin curing behaviors were evaluated. A model developed in this study, T_p = 53.296 exp(?9.72C) + 93.104, could be used to predict the resin curing rate in terms of the DSC peak temperature (T_p) as influenced by the NH₄Cl content (C). The results indicated that the curing rate of UF resin increased as the catalyst content increased and reached a maximum when the catalyst content ranged from 0.5 to 1.0% (solid basis over liquid UF resin weight). Further increases in the catalyst content had no effect on the resin curing rate. The curing rates of UF resin in the presence of wood extracts increased with decreased pH values or increased base buffer capacities. It was also discovered that the activation energy could not fully explain the resin curing behavior when some species of wood extracts were present, and therefore, the pre‐exponential factor had to be taken into account. The concept of the equivalent catalyst content (ECC) of wood extracts to the NH₄Cl content was introduced in this study; ECCs ranged from 0.0022 to 0.0331% among the 16 wood species. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Synthesis of novel phosphorus-containing cyanate esters and their curing reaction with epoxy resin

Novel phosphorus-containing cyanate esters with phosphorus contents between 1-4% (badcyp_x, x=1-4) were synthesized from the addition reaction of 9,10-dihydro-9-oxa-10-phosphaphenanthrene 10-oxide (dopo) and bisphenol A dicyanate (badcy). The structures of synthesized cyanate ester resins were confirmed by NMR and IR spectra. The modified cyanate esters were either self-curing (badcy and badcyp_x series) or curing with epoxy (badcye and badcyp_xe series). Thermal properties of cured cyanate ester were evaluated by differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), thermal gravimetric analysis (TGA), dielectric analyzer (DEA) and UL-94 vertical test. It was found that T_g and T_d (5%) decrease markedly with the phosphorus content for the self-curing system, while T_g and T_d (5%) decrease slightly with the increase of cyanate equivalent weight for the cyanate-epoxy curing system. The flame retardancy increases with the phosphorus content and a UL-94 V-0 rating can be achieved for cured badcyp₂-badcyp₄ and badcyp₃e-badcyp₄e. These flame retardant thermosets exhibit low moisture absorption as well as low dielectric constants and dissipation factors. Experimental results indicate that introducing the flame retardant phosphorus element into cyanate ester will not sacrifice its low dielectric characteristic.     

Al2O3/h-BN/epoxy based electronic packaging material with high thermal conductivity and flame retardancy

The long-term and stable operation of integrated circuits and microelectronics requires packaging epoxy resin (EP) exhibit high thermal conductivity for efficient heat dissipation, and excellent flame retardancy in case of thermal runaway. We achieved such EP composite via filling poly-dopamine (PDA) modified nanoscale Al₂O₃ spheres and microscale h-BN sheets. The PDA modification increases the compatibility between fillers and EP and largely reduces the viscosity, improving the dispersion of fillers in EP thus the thermal conductivity of EP composites. In addition, NH₃, H₂O, and N₂ generated during the combustion of phenolic hydroxyls and aminos in PDA combined with the physical barrier effect of Al₂O₃ and h-BN can improve the flame retardancy of EP composites. As a consequence, the EP composite filled with PDA modified Al₂O₃ (26.67 wt%) and h-BN (13.33 wt%) (i.e., PDA-BNAO/EP) shows a thermal conductivity of 1.192 W/mK (654.9% of EP), a peak heat release rate of 194.9 W/g (33.8% of EP), and total heat release of 15.2 kJ/g (54.5% of EP), respectively. What's more, the viscosity of PDA-BNAO/EP is 20,443 mPa s, which is only 20% of BNAO/EP (whose viscosity is 102,281 mPa s). More importantly, the PDA-BNAO/EP has good dynamic mechanical properties with the storage modulus of 14.69 Gpa, glass transition temperature of 91.9°C and good electrical insulation, which is desired for packaging of microelectronics. PDA-BNAO/EP composite should be a promising candidate for widespread packaging materials of microelectronics.     

Development of heat shrinkable and flame‐retardant EVA/CSM blends

A plastic (EVA) was blended with elastomer (CSM) with and without curatives. The elastomer phase (amorphous) contributed markedly to the shrinkability and most important is, took up a major amount of additive flame‐retarding agent thus not affecting much the heat shrinkability of the plastic i.e. as a whole the blend. When the elastomer phase was crosslinked the flame‐retardancy, due to a reduction of combustible volatile product, was increased. Additive flame‐retardants hamper the heat‐shrinkability of the blend to some extent depending on various factors such as blend composition, temperature, curing etc. The depression of shrinkability in the presence of flame‐retarding agent was less for the cured sample and elastomer‐rich blend compared with the uncured and plastic‐rich blend, respectively. It was found that with an increase in the cure time and elastomer content the shrinkability as well as flame‐retardancy was increased. At high temperature the sacrifice of the shrinkability in the presence of flame‐retardants increased, for a particular blend. The shrinkability and flame‐retardancy of a cured sample was higher than that of an uncured sample. The highest flame‐retardancy was obtained in the presence of Sb₂O₃/Chlorohor. Copyright © 2002 John Wiley & Sons, Ltd.     

Modeling solid–liquid equilibrium of NH4Cl‐MgCl2‐H2O system and its application to recovery of NH4Cl in MgO production

A new method to recover NH₄Cl from NH₄Cl‐rich aqueous solutions generated in the magnesia (MgO) production is developed on the basis of modeling the solid–liquid equilibrium (SLE) for the NH₄Cl‐MgCl₂‐H₂O system with the Pitzer model embedded in Aspen Plus? platform. The SLE values for the ternary system were determined from 278.15 to 348.15 K. The new standard‐state chemical potentials of NH₄Cl and MgCl₂·6H₂O were judicially obtained. The resulting equilibrium constants were used to determine new interaction parameters for the NH₄Cl‐H₂O and MgCl₂‐H₂O systems. These new parameters, together with the mixing parameters determined from correlating the experimental values, were used to correlate the equilibrium constant for NH₄MgCl₃·6H₂O, which plays a key role in NH₄Cl recovery. The results could extend SLE calculation for the NH₄Cl‐MgCl₂‐H₂O system from 278.15 to 388.15 K, satisfying the process identification and simulation requirement involved in the recovery process. The phase‐equilibrium diagram generated by modeling was illustrated to identify the process alternatives for recovering NH₄Cl. The resulting course to recover NH₄Cl by three fractional crystallization operations was finally proved feasible. © 2010 American Institute of Chemical Engineers AIChE J, 2011.     

Flame retardancy in fabric consisting of cellulosic fiber and modacrylic fiber containing fine‐grained MoO3 particles

Flame retardancy of fabrics consisting of modacrylic fiber containing with various dispersed metal compounds and cellulosic fiber has been investigated by means of flame test (ISO15025 procedure A) and limiting oxygen index (LOI). It has been found that excellent flame retardancy is achieved by fine‐grained MoO₃ particles. The afterflame time in flame test and the LOI value are improved with decreasing particle size of MoO₃. The flame retardancy of MoO₃ (particle size; 0.1 µm) is comparable to that of Sb₂O₃. On the other hand, significant improvement in flame retardancy is not observed for other metal compounds although some metal oxides and a hydroxide in the present study are known as flame retardant or smoke suppressing agent in halogen containing polymer in previous studies. In order to clarify the mechanism of the observed flame retardancy by the addition of fine‐grained MoO₃, we have carried out X‐ray fluorescence spectrometry (XRF) measurement of the fabric specimen after the flame test and thermogravimetric analysis (TGA) of various types of samples. These analytical data indicated that MoO₃ works as halogen synergist in solid phase and the char of modacrylic fiber formed by addition of MoO₃ suppresses decomposition of the cotton blended in the fabric in the range of the ignition temperature. Copyright © 2015 John Wiley & Sons, Ltd.     

Improving thermal and flame‐retardant properties of epoxy resins by a new imine linkage phosphorous‐containing curing agent

A new reactive phosphorus‐containing curing agent with imine linkage called 4, 4′‐[1, 3‐phenyl‐bis(9, 10‐dihydro‐9‐oxa‐10‐phosphaphenanthrene‐10‐yl)dimethyneimino)]diphenol (2) was synthesized both via two‐pot and one‐pot procedure. The chemical structure of this curing agent was confirmed by FTIR, ¹H, ¹³C, and ³¹P NMR spectra. A series of thermosetting systems were prepared by using conventional epoxy resins (E51), 4, 4′‐diaminodiphenyl methane (DDM) and (2). Resins with different phosphorus contents were obtained by changing the DDM/(2) molar ratios. Their dynamic mechanical thermal, thermal and flame‐retardant properties were evaluated by dynamic mechanical thermal analysis (DMTA), thermogravimetric analysis (TGA), and limiting oxygen index (LOI), respectively. All samples had a single T_g, which showed that these epoxy resins were homogeneous phase. Both the two char yields under nitrogen and air atmospheres increased with increasing content of (2) and the LOI values increased from 24.5 for standard resin to 37.5 for phosphorus‐containing resin, which indicated that incorporation of (2) could impart good thermal stability and excellent flame retardancy to the conventional epoxy thermosets. POLYM. ENG. SCI., 56:441–447, 2016. © 2016 Society of Plastics Engineers     

Effect of MAA/MAM pregrafting on DMEU finishing of cotton fabrics

Cotton fabrics were pregrafted with mixed monomer of methacrylic acid (MAA) and N-methylolacrylamide (MAM) before undergoing finishing with 1,3-dimethylolethylene urea. Experiments show that when the molar ratio of MAA and MAM is 4 : 6 the finished fabric has the maximum nitrogen content (N%) and crosslinking density. The pregrafting can improve the wet crease recovery angle and the moisture regain, can reduce the tensile strength retention, and has little effect on the dry crease recovery angle. In addition, at a pregrafting ratio of 4 : 6, the finished fabric has the highest crease recovery angle and moisture regain. © 1995 John Wiley & Sons, Inc.