Polyester polyols for waterborne polyurethanes and hybrid dispersions

In this study, environmentally friendly polyester based polyurethane dispersions (PUDs) were synthesized using various combinations of isophthalic acid, adipid acid and maleic anhydride (IPA-AA-MA). A triangular empirical model was employed to optimize total number of experiments for optimal performance of polyurethane dispersions. In addition to PUDs, polyurethane/acrylate hybrid dispersions (PU/AC) were synthesized using graft copolymerization method to enhance the performance/properties of PUDs and for potential cost benefit.     

Development and characterization of phosphorus-containing siliconized epoxy resin coatings

The objective of the present work is the development and characterization of siliconized epoxy-phosphorus based bismaleimide coating systems using diglycidylether terminated poly (dimethylsiloxane) (DGTPDMS) and phosphorus-containing bismaleimide (PBMI) as chemical modifiers for epoxy resin. Phosphorus-containing diamine (DOPO-NH₂) was synthesized from 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) and 4,4′-diaminobenzophenone (DABP), which was utilized in the preparation of phosphorus-containing bismaleimide (PBMI) with maleic anhydride. Siliconized epoxy prepolymer was prepared using epoxy resin and functionally terminated polydimethylsiloxane. The purity and structural conformation of these materials were ascertained from FTIR and NMR spectral studies. The prepared siliconized epoxy prepolymer was blended with varying percentages of PBMI using diaminodiphenylsulfone (DDS) and diaminodiphenylmethane (DDM) as curing agents. The siliconized epoxy and bismaleimide modified epoxy and siliconized epoxy coating materials were characterized by dynamic mechanical thermal analysis (DMTA), differential scanning calorimetry (DSC), thermo gravimetric analysis (TGA), heat distortion temperature (HDT) and Limiting oxygen index (LOI).     

Synthesis and characterization of triazole rich polyether polyols using click chemistry for highly branched polyurethanes

The present work describes development of moisture cured polyurethane–urea coatings based on 1,2,3-triazole rich polyether polyols. In this paper, two polyether polyols were synthesized by using 1,3-dipolar azide–alkyne cycloaddition reaction and they were named as PL-1 and PL-2 where PL-1 is 9 terminal hydroxyl groups and PL-2 is 6 terminal hydroxyl groups. These polyols were reacted with 4, 4′-diisocyanatodicyclohexylmethane (H₁₂MDI) at OH:NCO ratio of 1:1.2 in order to obtain isocyanate terminated polyurethane prepolymers. The resulted prepolymers were casted on tin foil and cured under atmospheric moisture in order to get completely cured polyurethane–urea free films. The free films were characterized by using Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA) and dynamic mechanical thermal analysis (DMTA) techniques. The TGA and DMTA results showed that these films have good thermal and mechanical stability. Anti-microbial studies proved that these polyurethane films show good resistance towards different bacterial and fungal attacks. These polymers were also coated on mild steel panels in order to evaluate corrosion resistance properties by using salt spray and electro chemical polarization studies.     

Novel triol-crosslinked polyurethanes and their thermorheological characterization as shape-memory materials

A new family of crosslinked polyurethanes was synthesized and characterized as shape-memory polymers. Three-arm network junctions are provided by 1,1,1-trimethylol propane with an isocyanate group on each arm. Three diisocyanates are used: 4,4′-methylene bis(phenyl isocyanate), toluene diisocyanate, and 4,4′-dibenzyl diisocyanate. They are linked together by macrodiol soft segments formed from either polytetrahydrofuran with molar mass of 650, 1000 or 2000 g mol⁻¹ or polycaprolactone glycol with molar mass of 830 or 1250 g mol⁻¹. Thermorheological response of each polymer was characterized by tensile creep tests through the glass transition of the soft segments, to obtain the linear viscoelastic retardation spectrum, limiting compliances and time-temperature shift factor. These were used to predict significant features of shape-memory performance. With a decrease in soft segment chain length, the temperature of maximum shape recovery rate increased and the width of the recovery window decreased, consistent with loss of soft segment chain mobility remote from the crosslinks. Tensile modulus in the switched condition (above T_g) was 8-16 MPa, increasing with crosslink density and hard-segment rigidity. The results confirmed the potential of these polyurethanes as a new family of tunable shape-memory materials.     

Soybean oil‐based shape‐memory polyurethanes: Synthesis and characterization

Shape‐memory polymers (SMPs) have wide range of applications due to their ability to sense environmental stimuli and reshape from a temporary shape to a permanent shape. Plant oil‐based polymeric materials are highly concerned in recent years in consideration of petroleum depletion and environmental pollution. However, plant oil‐based polymers are rarely investigated regarding their shape‐memory characteristics though bio‐based SMPs are highly desired nowadays. In this study, a series of soybean oil‐based shape‐memory polyurethanes (SSMPUs) are prepared through a mild chemo‐enzymatic synthetic route, and their properties are fully characterized with tensile testing, DSC, dynamic mechanical analysis (DMA), and shape‐memory testing. Results show that SSMPUs are soft rubbers with tensile strength in the range of 1.9–2.2 MPa and glass transition temperature in the range of 2–5°C, and possess good shape recoveries at RT when stretching ratio is 10, 20, and 30%, respectively. This work would promote the development of high‐value‐added plant oil‐based shape‐memory polyurethanes. Practical applications: Using annual renewable plant oil as feedstock, the synthesized SSMPUs show good shape recovery properties, which will make them applicable as potential alternatives to petroleum‐based shape‐memory materials. The simple and mild preparation process also contributes to the further exploration of plant oil to value‐added functional materials.     

Synthesis of a novel phosphorus-containing polymer and its application in amino intumescent fire resistant coating

A mixture (denoted as PX) of phosphates was prepared by the reaction of phosphoric acid and a kind of bicyclic pentaerythritol phosphate (PEPA, 1-oxo-1-phospha-2,6,7-trioxabicyclo[2.2.2]-4-hydroxymethyl octane). Then PX was successfully copolymerized with PEG200 to achieve a novel phosphorus-containing polymer (denoted as PX-co-PEG). ³¹P NMR, ¹H NMR and FT-IR analysis results showed that there were 38.7 wt.% PEPA phosphates and 61.3 wt.% pentaerythritol biphosphates in the PX mixture. The result of GPC indicated that the molecular formula of PX-co-PEG could be noted as PX_2.0PEG_3.0. Fire protection test results proved that PX-co-PEG modified amino resin applied on the plywood boards effectively extended the protection time over flame. The decomposition process of fire resistant coating was studied by thermogravimetric analysis and FT-IR which could be divided into three characteristic temperature stages. The solid residue was kept to be 14.6 wt.% at 787 °C.     

Synthesis and shape memory effects of Si-O-Si cross-linked hybrid polyurethanes

A series of novel Si-O-Si cross-linked organic/inorganic hybrid polyurethanes (HYPUs) with shape memory effect were prepared from isophorone diisocyanate (IPDI), poly(ethylene oxide) (PEO), and a newly synthesized hybrid diol (HD) containing hydrolysable Si-OEt groups. After hydrolyzation and condensation of Si-OEt groups, the resulted films were characterized using wide-angle X-ray scattering (WAXS), differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA) and shape recovery test to get the insight into the relationship between shape memory behaviors and polymeric structures. The glass transition temperatures (T_g) and storage modulus increased with Si-O-Si cross-linking increasing in the hybrid polyurethanes. The hybrid polyurethanes can recover to their original shapes almost completely in less than 40 s in atmosphere and in less than 10 s in water, respectively, when heated at 25 °C above T_g. The shape memory mechanism is coming from the freezing at low temperature and activation at high temperature of micro-Brownian movement of amorphous molecular chains since the temperature ranges at which the sharpest changes of recovered curvature happened are found to be around their glass transition range. The high ratio of storage modulus below and above accounted for the temporary shape fixing at low temperature. The samples with more Si-O-Si cross-linking have higher storage modulus at high temperature, resulting in faster shape recovery speed but lower temporary shape fixing.     

Synthesis and characterization of flame retardant hyperbranched polyurethanes for nano-composite and nano-coating applications

Flame retardant hyperbranched polyurethanes were prepared by reacting phosphorous containing triol, tris(bisphenol-A) mono phosphate, castor oil, and polyethylene glycol with different diisocyanates like TDI, IPDI and HMDI via A₂+B₃ method. In this method A₂ reactants were diisocyanates along with castor oil and polyethylene glycol whereas phosphorous containing triol was used as B₃ reactant and dibutyltin dilaurate (DBTDL) was used as catalyst. Synthesized polyurethans were characterized by gel-permeation chromatography (GPC), elemental analysis, Fourier transform infrared spectroscopy (FTIR) and ¹H NMR spectroscopic techniques. Neat polyurethanes were used for preparing films. Nano-clay composites were prepared with various concentration of organomodified montmorillionite nano-clay. Flame retardant, Thermal and mechanical properties of these hyperbranched polyurethanes and their nano-composites were found out. The polyurethanes and their formulations with nano-clay were also used for the coating of mild steel panels. Scratch, pencil, and impact hardness, flexibility and adhesion properties of coated panels were also determined. Observations show an increase in the scratch hardness and flexibility with the introduction of clay. All the coatings show excellent chemical resistance properties compare to their linear counterpart.     

聚硅氧烷/聚醚聚氨酯弹性体的合成与表征

以聚二甲基硅氧烷(PDM S)与聚丁醚(PTM G)为混合软段与4,4'-二苯甲基二异氰酸酯(M D I)、1,4-丁二醇(1,4-BD)制备出一系列的聚氨酯共聚物。用FT IR、DM A、TGA以及AFM分别对共聚物的结构、热性质以及表面形态进行了表征。结果表明,共聚物含有复杂的微相分离结构,而且与纯聚氨酯相比,含硅氧烷的聚氨酯比纯聚氨酯具有更好的热稳定性。     

Synthesis of some novel silicone-imide hybrid inorganic–organic polymer and their properties

Synthesis and properties of poly(imide-siloxane) hybrid polymers (PIS), having alternate diimide and disiloxane units, based on 1,3-bis(succinyl anhydride)1,1,3,3-tetraorganodisiloxane (I or II) have been described. Polymers have been synthesized by the precursor synthesis i.e., poly(amic acid), using siloxanes (I or II) and 4,4′-diaminodiphenylmethane (DDM) or 4,4′-diaminodiphenylsulphone (DDS) in N,N-dimethylacetamide (DMAc) followed by thermal imidization. FT-IR, thermal (TGA and TMA), solvent resistant and dielectric properties of the compounds have also been studied. The glass transition, thermal stability and char yields of these hybrid polymers increased appreciably. These materials also showed very good solvent resistant properties in protic and aprotic solvents.     

Synthesis and characterization of metal‐containing polyurethanes with antibacterial activity

Metal salts of mono(hydroxypentyl)phthalate [M(HPP)₂, where M is Ca²⁺, Cd²⁺, Pb²⁺, or Zn²⁺] were synthesized by the reaction of 1,5‐pentane diol, phthalic anhydride, and metal acetate. A new series of metal‐containing polyurethanes containing ionic links in the main chain were synthesized by the reaction of hexamethylene diisocyanate or toluylene 2,4‐diisocyanate with the M(HPP)₂ salts. The structures of the monomers and polymers were confirmed with infrared, ¹H‐NMR, and ¹³C‐NMR spectra and elemental analysis. The polymers were also characterized with thermogravimetric analysis, differential scanning calorimetry, and solubility and viscosity measurements. The antibacterial activity of these polyurethanes was investigated with the agar diffusion method. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 1194–1206, 2002     

Synthesis and characterization of some polyurethanes

Polymers containing urethane units were synthesized by solution polymerization of bisphenols A, C, and F with diisocyanates viz. toluene-2,4-diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, and diphenylmethane diisocyanate, respectively. Thus obtained polymers were pale yellow amorphous powders. These polymers were characterized by infrared spectral studies and nitrogen content. The number-average molecular weights (M?_n) were estimated from conductometric titration and limiting viscosity number [η] in dimethyl formamide. From thermogravimetric analyses, the thermal behaviour was studied. Kinetic parameters for their degradation were computed.     

温度、pH及离子强度敏感性聚氨酯水凝胶的合成与性能研究

以甲苯二异氰酸酯(TDI)、聚乙二醇(PEG-6000)、二羟甲基丙酸(DMPA)及三乙撑四胺(TEFA)等为原料,合成了温度、pH、及离子强度敏感性聚氨酯水凝胶(PUHG)。研究了PUHG溶胀率(SR)受温度(T)、pH、离子强度(I)、交联剂用量等因素的影响。结果表明PUHG的溶胀率在20~45℃的范围内随温度的升高而减小,45℃后不再变化;在酸性(pH4)溶液中收缩,在碱性(pH9)溶液中溶胀,表现出良好的pH值敏感性;在一定温度和pH下,随着离子强度的增加PUHG的溶胀率减小。水凝胶溶胀动力学研究表明,PUHG具有良好的溶胀-退胀可逆性。     

Synthesis and characterization of new polymethacrylates bearing perfluorocyclobutyl and sulfonyl units

A new methacrylate monomer containing perfluorocyclobutyl and sulfonyl units, p-(2-(p-(benzenesulfonyl)phenoxy)perfluorocyclobutoxy)phenyl methacrylate, was synthesized from commercially available reagents in good yield and this kind of methacrylate can be homopolymerized by free radical polymerization using 2,2′-azobis(isobutyronitrile) as initiator or atom transfer radical polymerization using methyl 2-bromopropionate as initiator and CuBr/PMDETA as catalytic system. The reactivity ratios for BSPPFCBPMA and MMA were found to be r₁ = 1.2436 and r₂ = 0.8171 determined by Fineman-Ross method, and r₁ = 1.2279 and r₂ = 0.8023 by Kelen-Tudos method respectively. The resultant polymethacrylates bearing perfluorocyclobutyl and sulfonyl functionalities exhibit excellent thermal stability as evidenced from thermogravimetric analysis and the decomposition temperature rose dramatically with the increasing of molecular weights. Random copolymers of BSPPFCBPMA and methyl methacrylate were obtained by free radical copolymerization and their thermo-stabilities increase while raising the contents of BSPPFCBPMA.     

Synthesis and evaluation of mechanical and thermal properties of segmented condensation polyurethanes

Abstract

Condensation polyurethanes with different hard segment (HS) content were prepared by condensation reaction of urea, phenol sulphonic acid and formaldehyde and tested for their mechanical, physical and thermal properties. Obtained polyurethane (PUR) films were first heated at 50°C for 120 min and then treated at 135°C for 15 min or 160°C for 10 min. The tensile strength of samples thermally treated at 50°C then at 135°C was 120% higher than for samples treated only at 50°C. The obtained polyurethanes exhibited segmented structures with phase separation between HSs and soft segments (SSs). Films containing 19 and 21%HSs heated at 50°C then 135°C exhibited acceptable mechanical properties and water resistance. The lower and higher end use temperatures of PUR films were affected mainly by the polymer composition. Moreover, the polyurethane samples containing 19 and 21%HSs have shown the highest decomposition temperature (i.e. >165°C), compared to 80°C for polymers with 32%HSs.     

丙烯酸乙基磷酸二乙酯的合成及其阻燃性能的研究

以三氯氧磷、丙烯酸羟乙酯和乙醇为原料,合成了丙烯酸乙基磷酸二乙酯;研究了物料比、反应温度、n(三乙胺)∶n(丙烯酸羟乙酯+乙醇)及反应时间等因素对合成反应的影响,采用FTIR对产物结构进行了表征,采用HPLC、碘量法测定了产物的纯度。结果表明:以二氯甲烷为溶剂,在n(三氯氧磷)∶n(丙烯酸羟乙酯)为1.2∶1、反应温度为15℃、n(三乙胺)∶n(丙烯酸羟乙酯+乙醇)为1.2∶1、反应时间为12h的条件下,可得到纯度为96%、产率为80%的丙烯酸乙基磷酸二乙酯单体。将制得的单体和常规丙烯酸酯类单体共聚制备本体阻燃型丙烯酸酯压敏胶,当丙烯酸乙基磷酸二乙酯单体添加量占其它单体总量的18%时,丙烯酸酯压敏胶的阻燃性能得到显著提高。     

Nonlinear optical polymers with novel benzoxazole chromophores II. Synthesis of polyurethanes with good thermal stability

Novel diol monomer having a π-conjugated benzoxazole ring, 2-(4-nitrophenyl)-6-[N,N-bis(2-hydroxyethyl)amino]benzoxazole was successfully synthesized to improve the thermally stability of nonlinear optical chromophores. Several polyurethanes bearing pendant benzoxazole chromophores were obtained by polyaddition of the diol to various aromatic diisocyanates. The thermal stability of these polyurethanes were monitored by thetrnogravimetry and IR spectroscopy, and compared with other polyurethanes having general pendant azo chromophores. The poled polyurethane films exhibited large and stable second-order nonlinear optical properties.     

Synthesis of polyurethanes by polyaddition using diol compounds with methacrylate-derived functional groups

To functionalize polyurethane, a novel synthetic reaction of diol compounds derived from methacrylates with various functional groups was investigated. The methacrylates were reacted with α-thioglycerol via a Michael-type addition to obtain the corresponding diol compounds under mild conditions. In this reaction, diisopropylamine was a much better catalyst than triethylamine. The conversion was dependent on the functional group in the methacrylate. The fluoroalkyl group in 2,2,2-trifluoroethyl methacrylate was better than the alkyl group in butyl methacrylate. No reaction was observed in the case of styrene. Using these diol compounds, polyurethanes were prepared by polyaddition with 4,4-diphenylmethane diisocyanate. When the polyurethanes were casted on the substrate, the functional groups influenced surface hydrophilicity and protein adsorption resistance property of the polyurethane significantly. In particular, phosphorylcholine group was the best to reduced protein adsorption. Based on these findings, the variety of these diol compounds synthesized from methacrylates has the potential for use in the production of novel polyurethanes.