Novel polyurethane polyols for waterborne and high solids coatings

Recently developed oligomeric β-hydroxyalkyl urethane polyols are finding application as modifiers and crosslinkers for waterborne and high solids coatings. In waterborne coatings, urethane polyols can be used as modifiers for acrylic, polyester or alkyd melamine resin crosslinked coatings to replace the cosolvent. In high solids coatings, polyurethane polyols are being employed to raise the application solids, increase film hardness and water resistance, and exterior durability.

There are also applications for polyurethane diols as resin intermediates and in the preparation of blocked isocyanate crosslinkers. β-Hydroxyalkyl urethane diol or polyols can be prepared by an isocyanate reaction with a diol, such as 1,2-propylene glycol, but also by non-isocyanate processes. The non-isocyanate routes to urethanes can utilize carbon monoxide, carbon dioxide, urea or organic carbonates as a carbonyl source for the carbamic acid ester.

It is possible to split these urethanes to the isocyanate, but interest has concentrated on using the urethane intermediates directly in coating applications without going through the isocyanate. The structures reported are bis-hydroxyalkyl urethane intermediates and derivatives of these compounds.     

Allyl phosphonium salt–modified clay for photocured coatings: Influence on the properties of polyester acrylate‐based coatings

In this study, bentonite clay was modified with a phosphonium salt and this modified clay was used to prepare polyester acrylate based coatings to improve their flame retardancy and mechanical properties. Photocured composites were prepared with 1, 2, and 3 wt% phosphonium salt modified clay and for comparison 1 wt% nonmodified clay containing composites were also prepared. Modified clay displayed good dispersion properties due to its increased basal spacing. Composites were characterized by FT‐IR and XRD measurements. According to XRD results, it was found that the modified clay was exfoliated in the composites. Furthermore, we investigated the effect of allyl phosphonium salt modified clay on the thermal, mechanical, and flame retardant properties of polyester acrylate based composites coatings. When compared with neat clay containing coatings, modified clay containing photocured coatings exhibited increased modulus and enhanced thermal properties due to increased crosslinking density. Moreover, the presence of the phosphonium salt enhanced the flame retardancy of the polyester based coatings. POLYM. COMPOS., 36:946–954, 2015. © 2014 Society of Plastics Engineers     

Flammability behavior of unsaturated polyesters modified with novel phosphorous containing flame retardants

Two phosphorous containing reactive flame retardants namely Triallyl phosphate (TAP) and diethylene glycol modified tetra‐allyl phosphate (DTAP) are synthesized and incorporated successfully in commercial Unsaturated polyester (UPR) in various amounts (5, 10, and 15 phr) to yield flame retardant unsaturated polyester (FRUPR) composites. The structures of reactive flame retardant monomers are confirmed by FTIR, ¹H‐NMR, and³¹P‐NMR spectroscopy. Further, FRUPR composites are characterized for their mechanical, thermal, and flame retardant properties. It is observed that tensile strength and hardness of composites are enhanced with the addition of flame retardants; however, flexural strength and impact resistance are lowered. Differential Scanning Calorimetry (DSC) study reveals that there is a significant increase in glass transition temperature with the addition of flame retardants suggesting the formation of dense and crosslinked structure in FRUPR composites. Thermal stability and the flame retardant properties are also observed to be improved with the increase in concentration of flame retardant in UPR as evidenced from Thermo‐gravimetric analysis (TGA). Beyond 10 phr concentration of flame retardants, all composites show V‐0 rating on UL‐94 test. Also, increase in phosphorous content in composites leads to gradual improvement in limiting oxygen index values. POLYM. COMPOS., 38:1483–1491, 2017. © 2015 Society of Plastics Engineers     

阻燃喷涂硬质聚氨酯泡沫的制备及在建筑工程的应用

采用结构型阻燃聚醚多元醇、聚酯多元醇、阻燃硅油、催化剂、发泡剂和阻燃剂等原料,通过一步法喷涂制备阻燃型喷涂硬质聚氨酯泡沫(RPUF)。研究了结构型阻燃聚醚多元醇和阻燃硅油对RPUF性能的影响,并在建筑工程中进行了实际应用。结果表明,以100份多元醇为基准,其它组分不变,结构型阻燃聚醚多元醇的添加量为30份、阻燃硅油的添加量为5份时,制备出的RPUF的物理性能、阻燃性能和储存性能最佳。另外,在建筑工程应用中,该产品性能及施工性能均良好。     

Syntheses and characterizations of two-component polyurethane flame retardant coatings using 2,4-dichloro modified polyesters

Polyurethane flame retardant coatings are composed of polyols and polyisocyanates. Flame retardant groups are usually introduced to the polyol structure. In this research intermediates were obtained by esterification of 2,4-dichlorobenzoic acid and trimethylolpropane for the purpose of introducing a flame retardant group to the polyol structure. Then chlorine-containing modified polyesters were synthesized by polycondensation of trimethylolpropane, adipic acid, 1,4-butanediol, and the intermediate. The content of 2,4-dichlorobenzoic acid in the intermediate was varied with 10, 20, and 30 wt%. Two-component polyurethane flame retardant coatings were prepared by blending the products with polyisocyanate. Various physical properties of these new flame retardant coatings were comparable to non-flame retardant coatings. They showed drying times of four to seven hours and pot life times of 14–20 hr, which could belong to the flame retardant coatings with long pot life time. The coating with 30 wt% 2,4-dichlorobenzoic acid showed a self-extinguishing property in the vertical burning test. Dept. of Chemical Engineering, Yongin 449-728, Korea. Ansan 425-110, Korea.     

Preparation and properties of transparent thermoplastic segmented polyurethanes derived from different polyols

Various segmented polyurethanes of different soft segment structure with hard segment content of about 50 wt% were prepared from 4,4′‐diphenylmethane diisocyanate (MDI), 1,4‐butanediol and different polyols with a M_n of 2000 by a one‐shot, hand‐cast bulk polymerization method. The polyols used were a poly(tetramethylene ether)glycol, a poly(tetramethylene adipate)glycol, a polycaprolactonediol and two polycarbonatediols. The segmented polyurethanes were characterized by gel permeation chromatography (GPC), UV‐visible spectrometry, differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), X‐ray diffraction, and their tensile properties and Shore A hardness were determined. The DSC and DMA data indicate that the miscibility between the soft segments and the hard segments of the segmented polyurethanes is dependent on the type of the soft segment, and follows the order: polycarbonate segments > polyester segments > polyether segments. The miscibility between the soft segments and the hard segments plays an important role in determining the transparency of the segmented polyurethanes. As the miscibility increases, the transparency of the segmented polyurethanes increases accordingly. The segmented polyurethanes exhibit high elongation and show ductile behavior. The tensile properties are also affected by the type of the soft segment to some extent. POLYM. ENG. SCI., 47:695–701, 2007. © 2007 Society of Plastics Engineers.     

Preparation of porous polyester composites via emulsion templating: Investigation of the morphological,mechanical, and thermal properties

Open porous polyester composites were prepared by the crosslinking of unsaturated polyester resin and divinylbenzene in water‐in‐oil concentrated emulsion templates with the presence of a conventional surface modified montmorillonite nanoclay. Medium and high internal phase emulsions with either 55 or 80 wt% of internal phase were used as templates. The effect of monomer composition, emulsifier concentration, and internal phase amount on the emulsion stability and the morphology of the resulting porous composites were investigated. Moreover, the morphological properties of the resulting composites were determined depending on the amount of nanoclay loading. It was found that the morphological features, namely surface area and cell diameter, were altered dramatically with the amount of nanoclay loading. An important part of the research was focused on the variation of mechanical and thermal properties with the incorporation of nanoclay particles. The mechanical properties were improved both with the nanoclay incorporation and the use of medium internal phase emulsions. However, the used nanoclay did not have a significant effect on the thermal stability of the resulting composites. POLYM. COMPOS., 37:1531–1538, 2016. © 2014 Society of Plastics Engineers     

Synergistic effects of polyethylene glycol and ammonium polyphosphate on intumescent flame‐retardant polypropylene

A novel flame‐retardant system of isotactic polypropylene (iPP) is prepared using polyethylene glycol (PEG) and ammonium polyphosphate (APP). The flammability of iPP/PEG/APP composites containing 20 wt% APP improves with the increase of PEG concentration in the range of 3–15 wt%. The limit oxygen index (LOI) of iPP/PEG/APP composites reaches up to 30% with 15 wt% PEG concentration in the composites. At the same time, the mechanical properties of iPP/PEG/APP composites demonstrate that PEG can enhance toughness of iPP/APP composites. The results of cone calorimetry prove the synergistic effects of PEG and APP on intumescent flame‐retardant iPP, and those of the thermogravimetric analysis(TGA) reveal that iPP/PEG/APP samples decompose faster than iPP/APP composites. Investigated by scanning electronic microscopy (SEM), the morphology and structures of residues generated during LOI tests confirm the formation of effective char layer, and that the improvement of the flame retardancy and the impact strength of the composites are thanks to the presence of PEG. POLYM. ENG. SCI., 2013. © 2012 Society of Plastics Engineers     

Preparation and characterization of polyurethane flame‐retardant coatings using pyrophosphoric lactone‐modified polyesters/isophorone diisocyanate–isocyanurate

Pyrophosphoric lactone‐modified polyester containing two phosphorous functional groups in one structural unit of base resin was synthesized to prepare a nontoxic, reactive flame‐retardant coatings. Then, the pyrophosphoric lactone‐modified polyester was cured at room temperature with isocyanate and isophorone diisocyanate (IPDI)–isocyanurate to get a two‐component polyurethane flame‐retardant coatings (TAPPU). Comparing the physical properties of the films of TAPPU with the film of nonflame‐retardant coatings, no deterioration of physical properties was observed with the incorporation of a flame‐retarding component into the resin. Three kinds of flame retarding tests were conducted, including the 45° Meckel burner method, limiting oxygen index method (LOI method), and oxygen combustion method with Cone calorimeter. It was observed that the char lengths were 3.1～4.5 cm and LOI values were 27～30%. These results indicate that the prepared coatings are good flame‐retardant ones. It was also found that the flame retardancy of those coatings was increased with the contents of phosphorous. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 2316–2327, 2001     

Effect of dicarboxylic acids on the performance properties of polyurethane dispersions

A series of low molecular weight linear polyester polyols were synthesized by using various diacids, neopentyl glycol, as a diol, and a trimethylol propane, as a branching monomer. Polyurethane dispersions were prepared primarily from isophorone diisocyanate, polyester polyol, and dimethylol propionic acid, as potential ionic center for water dispersibility, and were subsequently chain extended with ethylene diamine. The effect of polyester polyols based on variable diacids, on the physico‐chemical and thermal properties of polyurethane dispersions were evaluated by hardness, flexibility, impact resistance, solvent resistance, thermogravimetric analysis, and differential scanning calorimetry. Particle size was evaluated by particle size analyzer. It was observed that the number of alkylene groups present in the polyester polyol soft segment in addition to its molecular weight had a pronounced effect on the particle size, physico‐chemical, and thermal properties. With a proper selection of the soft segment, it is possible to fine‐tune properties of aqueous polyurethane dispersion coatings with respect to the final application. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Studies on thermal degradation and flame retardant behavior of the sisal fiber reinforced unsaturated polyester toughened epoxy nanocomposites

Unsaturated polyester (UP) toughened nanocomposites were prepared using both sisal fibers and montmorillonite clays. The effect of fibers and Cloisite 30B (C30B) nanoclays on the mechanical properties, thermal stability, flame retardant, and morphological behavior of the UP toughened epoxy (Epoxy/UP) were systematically studied. The chemical structures of Epoxy, UP, and Epoxy/UP systems were characterized using Proton Nuclear magnetic resonance (¹HNMR) and Fourier transform infrared (FTIR) spectra. The homogeneous dispersion of nanoclay within the polymer matrix was analyzed using transmission electron microscopy (TEM) and X‐ray diffraction (XRD) analysis. Incorporation of sisal fibers and C30B nanoclays within Epoxy/UP system resulted in an increase in the mechanical, thermal, and flame retardance properties. Thermogravimetric analysis (TGA) has been employed to evaluate the thermal degradation kinetic parameters of the composites using Kissinger and Flynn‐Wall‐Ozawa methods. Cone calorimeter, UL‐94, and LOI tests revealed a reduction in the burning rate of the matrix with the addition of fibers and nanoclays. The results showed that the treated fiber reinforced nanocomposites had higher thermal stability and better flame retardant properties than the treated fiber reinforced composites. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42068.     

阻燃型PETMF/WPU复合材料的制备与性能研究

用聚酯/碱溶性聚酯（PET/COPET）海岛纤维无纺布含浸含磷自阻燃的水性聚氨酯（WPU）浆料，通过干法凝固、碱减量和后整理等工艺制备阻燃型聚酯超细纤维/水性聚氨酯（PETMF/WPU）复合材料。分析并探讨不同固含量含磷自阻燃的WPU浆料对PETMF/WPU复合材料的阻燃性能和力学性能的影响。采用锥形量热仪、极限氧指数和垂直燃烧对其阻燃性能进行表征；采用电子扫描显微镜对其微观结构进行表征；采用TGA对其热稳定性进行表征。结果表明：当固含量达到35wt%时，PETMF/WPU复合材料的LOI值达到31.7%，垂直燃烧达到V-0级，在燃烧过程中能够自熄且无熔滴产生，力学性能仍能满足行业标准，使用含磷自阻燃原料减少了燃烧过程中有害气体的释放。     

Synergistic effect of aluminum hydroxide and nanoclay on flame retardancy and mechanical properties of EPDM composites

The composites based on ethylene–propylene–diene monomer rubber (EPDM) with aluminum hydroxide (ATH), nanoclay, vulcanizing agent, and curing accelerator were prepared by conventional mill compounding method. The thermal stability and the flame retardant properties were evaluated by thermogravimetric analysis (TGA), limiting oxygen index (LOI), UL‐94 test, cone calorimeter, and smoke density chamber tests. The results indicated that the substitution of the nanoclay in the EPDM/ATH composites increased the 50% weight loss temperature and the LOI value, and reduced the peak heat release rate (pk‐HRR), the extinction coefficient (Ext Coef), the maximal smoke density (Dm), and the whole smoke at the first 4 min (VOF4) of the test specimens. The synergistic flame retardancy of the nanoclay with ATH in EPDM matrix could imply that the formation of a reinforced char/nanoclay layer during combustion prevents the diffusion of the oxygen and the decomposed organic volatiles in the flame. The mechanical properties of the composites have been increased by replacing more of the nanoclays into the EPDM/ATH blends. The best loading of the nanoclay in EPDM/ATH composites is 3 wt %, which keeps LOI in the enough value, the V‐0 rating in the UL‐94 test, and the improved mechanical properties with better dispersion and exfoliation of the nanoclays shown by transmission electron microscopy (TEM) micrographs. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 2042–2048, 2013     

Thermomechanical properties of alkali treated jute‐polyester/nanoclay biocomposites fabricated by VARTM process

A systematic study was carried out to investigate the effect of alkali treatment and nanoclay on thermomechanical properties of jute fabric reinforced polyester composites (JPC) fabricated by the vacuum‐assisted resin transfer molding (VARTM) process. Using mechanical mixing and sonication process, 1% and 2% by weight montmorillonite K10 nanoclay were dispersed into B‐440 premium polyester resin to fabricate jute fabric reinforced polyester nanocomposites. The average fiber volume was determined to be around 40% and void fraction was reduced due to the surface treatment as well as nanoclay infusion in these biocomposites. Dynamic mechanical analysis (DMA) revealed enhancement of dynamic elastic/plastic responses and glass transition temperature (T_g) in treated jute polyester composites (TJPC) and nanoclay infused TJPC compared with those of untreated jute polyester composites (UTJPC). Alkali treatment and nanoclay infusion also resulted in enhancement of mechanical properties of JPC. The maximum flexural, compression, and interlaminar shear strength (ILSS) properties were found in the 1 wt % nanoclay infused TJPC. Fourier transform‐infrared spectroscopy (FT‐IR) revealed strong interaction between the organoclay and polyester that resulted in enhanced thermomechanical properties in the composites. Lower water absorption was also observed due to surface treatment and nanoclay infusion in the TJPC. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Effect of glycol and filler types on some polymeric composite properties

Two unsaturated polyesters based on maleic anhydride, phthalic anhydride, and sebasic acid with each of linear 1,6‐hexanediol (PE_L) and cyclic 1,4‐cyclohexanediol (PE_C) were prepared. Their structures were characterized by IR and ¹H NMR spectra. Their composites were prepared by mixing different ratios (60, 70, and 80%) with talc and kaolin with polyester/styrene mixture. The effect of linear and cyclic glycols and the effect of filler type and concentration of these composites were studied in terms of their electrical properties and the hardness before and after aging. The thermal behavior of styrenated polyesters and their composites was studied using thermogravimetric analysis. It has been found that both fillers increase the thermal stability and decrease the weight loss. The permittivity ε′ and the dielectric loss ε″ were measured in the frequency range 100 Hz up to 100 kHz at room temperature 25°C ± 1. The polyester composite samples containing 70% filler lead to good electrical properties in addition to its resistance to thermal aging. The hardness value was increased by increasing the filler content before and after aging. The polyester composites based on cyclic glycol and loaded with 80% kaolin gave the highest hardness values. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

膨胀型阻燃剂/二乙基次磷酸铝阻燃改性不饱和树脂基复合材料

采用密胺包覆聚磷酸铵（APP）、季戊四醇（PER）和三聚氰胺（MEL）作为膨胀型阻燃剂（IFR）对不饱和树脂（UP）进行改性,研究了APP、PER和MEL不同复配比例及用量对不饱和树脂基复合材料阻燃性能和力学性能的影响。基于IFR最佳用量,以二乙基次磷酸铝（ADP）为协效剂,研究了ADP用量对IFR/UP阻燃复合材料阻燃性能、力学性能及热稳定性的影响。结果表明,当APP∶PER∶MEL复配比例为4∶1∶1,IFR添加量为15 %（质量分数,下同）时,复合材料综合性能最佳,其极限氧指数为27.4 %,UL 94垂直燃烧达到V?1等级,弯曲强度和冲击韧性分别为100.3 MPa和6.3 kJ/m²;ADP的引入能够进一步提高IFR/UP复合材料阻燃性能,且随着ADP质量分数的增加而增强;当ADP质量分数为2 %时,IFR?ADP/UP复合材料极限氧指数为28.5 %并达到V?0阻燃等级,弯曲强度和冲击韧性分别为110 MPa和7.8 kJ/m²,与IFR/UP复合材料相比,分别提高了9.7 %和23.8 %;ADP能够促进IFR/UP复合材料表面成炭,缓解基体的热降解。     

生物基阻燃聚酯多元醇聚氨酯硬泡在煤矿中的应用

用生物基阻燃聚酯多元醇替代石油基聚醚多元醇添加于聚氨酯硬泡组合聚醚中,研究了该生物基阻燃聚酯多元醇的替代量,以及在煤矿中阻燃效果。结果表明,生物基聚酯多元醇可替代部分石油基聚醚多元醇使用,当生物基聚酯多元醇在总聚醚多元醇体系中占40%~50%时,聚氨酯泡沫的压缩强度高、尺寸稳定性良好、导热系数低且阻燃效果理想,达到中华人民共和国煤炭行业MT-113—1995标准,保证了煤矿安全使用。     

Preparation of aluminum diethyl hypophosphite intercalation-modified montmorillonite AlPi-MMT and its effect on the flame retardancy and smoke suppression of thermoplastic polyester elastomer

An aluminum diethyl hypophosphite intercalation-modified montmorillonite flame retardant (AlPi-MMT) is successfully prepared and characterized by FT-IR, SEM, and X-ray diffraction. It is found that thermoplastic polyester elastomer (TPEE) composites incorporating 15 wt% AlPi-MMT flame retardant exhibited better char formation and flame retardant properties compared to those incorporating 15 wt% (4:1, w:w) AlPi and MMT. And the char residual of TPEE/AlPi-MMT at 700°C is 16.17%, which is higher than that of TPEE/AlPi-MMT at 13.94%. and the former can pass UL-94 V-0 rating test while the latter can only pass UL-94 V-1 rating test. Afterwards, the combustion performance of TPEE composites is characterized, and it is found that the heat release and smoke release of TPEE/AlPi-MMT are greatly reduced compared with those of pure TPEE and TPEE/AlPi/MMT, which is a flame retardant and smoke suppressant TPEE composite. Finally, by analyzing the residual char morphology and elements of TPEE composites after combustion, the mechanism of the flame retardant AlPi-MMT to promote char formation and flame retardancy is demonstrated.     

Synthesis and properties of UV-curable waterborne unsaturated polyester for wood coating

UV-curable waterborne unsaturated polyesters for wood coatings were prepared. The effects of different polyols and acids on the properties of the UV-curable waterborne unsaturated polyesters were investigated. Several different unsaturated polyester prepolymers were prepared from three different polyols [ethylene glycol (EG), diethylene glycol (DEG), and propylene glycol (PG)] and three different acids [tetrahydrophthalic anhydride (THPAn), terephthalic acid (TPA), and trimellic anhydride (TMAn)]. UV-curable coating materials were formulated from the prepolymers and 2-hydroxy-2-methylphenyolpropane-1-one as a photoinitiator with distilled water as a diluent. Trimethylolpropane diallyl ether was used as an air inhibitor of cure. The dynamic mechanical studies showed the properties of those unsaturated polyesters were well correlated with their glass transition temperature behaviors. It was found that the unsaturated polyester prepared with 60/40 (mol %) TMAn/THPAn and the equimolar mixture of EG, DEG, and PG showed balanced coating properties such as good tensile properties and weatherability, as well as proper viscosity (ca. 2500 cps) when using distilled water as a diluent. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 69: 695–708, 1998     

苯酐聚酯多元醇聚氨酯硬泡的阻燃性研究

以国产苯酐聚酯多元醇为主要原料制备了组合聚醚,再与多异氰酸酯反应,制备了阻燃型聚氨酯硬质泡沫。讨论了苯酐聚酯多元醇、硅油及发泡剂等因素对泡沫阻燃性的影响。结果表明,该组合聚醚与多异氰酸酯反应,制得的阻燃型聚氨酯硬质泡沫,其氧指数在28以上,压缩强度为300kPa,达到了国家标准GB／T8624-1997中B2级氧指数的要求。