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A novel class of thermosetting resins based on allylated and transesterified epoxidized soybean oil (AE-ESBO) curable by radical mechanism was developed. The AE-ESBO was prepared from ESBO by oxirane ring-opening and then transesterification with allyl alcohol. A family of rubbery to glassy resins was prepared by radical copolymerization of AE-ESBO with different concentrations of maleic anhydride (MA). Glass transition temperatures (Tg) of these resins ranged from below room temperature to about 130°C based on the amount of MA. In spite of the presence of anhydride groups, water absorption was low

A new class of biopolymers based on plant oils with allylic double bonds was prepared from vegetable oils by oxirane ring-opening. Investigation of model systems revealed that the main side reactions during ring-opening were formation of intramolecular cyclic ethers in epoxidized linoleic fatty ester and oligomerization. Side reactions in the epoxidized oleic fatty ester were insignificant. Allyl alcohol ring-opened epoxidized soybean oil (AESBO) was then copolymerized with maleic anhydride (MA) to prepare thermosetting resins by free radical polymerization and esterification. In the best case, high gel content (99%), low water absorption (∼1%), and low swelling ration in toluene (∼4%) were achieved. Glass transition temperatures of these resins ranged from below room temperature to about 123 °C depending on the loading of MA. Tensile modulus varied from few MPa to 1.1 GPa, with the highest tensile strength of 29 MPa.

Thermoplastic urethanes based on polyricinoleic acid soft segments and MDI/BD hard segments with varied soft segment concentration were prepared. Soft segment concentration was varied from, 40 to 70 wt%. Biodegradation was studied by respirometry. Segmented polyurethanes with soft segments based on polyricinoleic acid degrade relatively slow losing about 11% carbon after 30 days, but faster than corresponding petrochemical polyesterurethanes. Since biodegradation proceeds mainly through the soft segments, higher soft segment content polymers displayed slightly higher biodegradation. Polyurethanes with dispersed hard domains in the soft phase displayed slightly faster biodegradation than those with co-continuous morphology. Polyester diol degrades slower than castor oil but significantly faster than the polyurethanes with built in soft segments from the same diol. Castor oil biodegrades slower than soybean oil.

To our knowledge, this is the first description of the material properties of a high molecular weight linear polyester prepared from the methyl ester of 9-hydoxynonanoic acid (HNME). The HNME of high purity was prepared by ozonolysis of castor oil, followed by methanolysis of triglycerides. High molecular weight polyester prepared in bulk by transesterification was a highly crystalline material with limited solubility in chlorinated solvents. The polyester is an analogue of polycaprolactone (PCL), but the longer hydrocarbon chain between ester groups imparted intermediate properties between polyesters and polyethylene, characterized by a higher melting point, higher Tg, better thermal stability, and lower solubility in chlorinated solvents than PCL. Differential scanning calorimetry showed only a single transition-melting at 70 °C with melting enthalpy of 95 J/g. Properties of the material were strongly dependent on the molecular weight. Lower molecular weight material was brittle with low mechanical stre...

In our previous publication on the structure–property behavior of segmented polyurethanes based on castor oil [Petrovic ZS, Xu Y, Zhang W. Polymer Preprints 2007;48(2):852–3.], the results showed that these materials which possessed a soft segment weight concentration (SSC) of 70% have both low tensile strength and elongation at break. This behavior is distinctly different from segmented polyurethanes of comparable soft segment content obtained from petrochemical polymeric diols that possess terminal hydroxyl groups. The poor elastic properties of these segmented polyurethanes were ascribed to the low molecular weight of the polymers as well as due to the presence of the six-carbon “dangling chain”, which may influence the morphology of the resulting segmented polyurethanes. To further understand this behavior, four segmented polyurethanes with the SSC of 70, 60, 50, and 40%, respectively, were synthesized from a polyricinoleate diol with an Mn of 2580, diphenylmethane diisocyanate (MDI) and butanediol. The objective of this work was to study the effect of SSC on the morphology of the resulting polyurethanes, and to correlate the morphology with the properties of these bio-based segmented polyurethanes. Polymers were characterized by GPC, viscometry and spectroscopic methods. Thermal and mechanical properties of the polymers indicated good microphase separation. Microphase morphology was also noted by SAXS and AFM. Finally, “spherulitic-like” superstructures were noted in the solution cast films that are believed to arise from the nucleation and crystallization of the hard segments.

Poly(ethyl acrylate) (PEA)/poly(methyl methacrylate) (PMMA) emulsion blends that were combined with unmodified montmorillionite (MMT) to improve the physical properties via nanocomposite formation. We prepared a cationic PEA/PMMA latex and used a heterocoagulation process to create a homogeneous dispersion of the clay platelets in the matrix. The cationic PEA/PMMA emulsion blends were prepared using a cationic initiator in the presence of free surfactant, cetyl trimethylammonium bromide (CTABr), followed by mixing with an aqueous slurry of MMT. The PEA/PMMA–MMT nanocomposites could be processed at low temperatures. Low temperature processing prevented the commonly observed discoloration associated with many thermoplastic nanocomposites. DSC, SAXS, TEM and AFM were used to study the dispersion of MMT and morphology of PEA/PMMA–MMT nanocomposites. Tensile stress, elongation at break and Young's modulus demonstrated a significant reinforcing effect of clay.

Polystyrene–carbon nanofiber (CNF) nanocomposites have been synthesized by a ‘bottom-up’ method through electrostatic assembly. First, a cationic polystyrene (PS) latex was synthesized by conventional emulsion polymerization. The latex was mixed with an aqueous suspension of oxidized CNF. PS–CNF nanocomposites were obtained by heterocoagulation due to the electrostatic interaction between cationic PS latex and anionic CNF. Thermal properties were characterized by DSC and TGA, while morphologies of the nanocomposites were studied by SEM. Electrical resistivity results showed that the percolation threshold in our PS–CNF nanocomposites was below 2 wt% (1 vol%). This low percolation threshold is related to the dispersion, and thus a superior network formation of CNF in PS matrix.

Poly(methyl methacrylate) (PMMA)–clay nanocomposites were prepared by a heterocoagulation method. A cationic PMMA emulsion was prepared by emulsion polymerization using a cationic initiator in the presence of free surfactant, cetyl trimethylammonium bromide (CTABr), followed by mixing with an aqueous clay slurry. Clays used in present research included montmorillonite (MMT), synthetic hectorites and fluorohectorites (with two different sizes). WAXD results and TEM images indicate that the morphologies of these nanocomposites depend on clay colloid stability as well as clay loadings. WAXD and TEM results also indicate the good morphology preservation of the nanocomposites during solution and melt processing. Thermal stability of these nanocomposites was studied by TG–DTG analyses; the mechanism of thermal stability improvement is discussed based on experimental results.

1,3-Dioxepane was polymerized with triflic acid as an initiator in the presence of acetic acid (AA) and hexane diacid. The structure of the poly(1,3-dioxepane) (polyDOP) obtained was characterized by 1H NMR spectra and gel permeation chromatography. The molecular weights (MWs) were determined by vapor pressure osmometry. The results obtained in both systems were completely different from those in which low-MW polyols were used as chain-transfer agents. When the molar ratio of carboxylic acid to triflic acid was low, high-MW polyDOP with a controlled MW and narrow MW distribution was obtained. The content of the ester group in the final product depended greatly on the molar ratio of AA to triflic acid. The polymerization mechanism is discussed. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 1232–1240, 2000

Poly (1,3-dioxepane) [PDOP] triol was prepared by cationic ring-opening polymerization with [C 2 H 5 C(CH 2 OCH 2 CH 2 CO + ClO - 4 ) 3 ], trioxocarbenium perchlorate, as an initiator. The structures of the PDOP triols obtained were verified by 1 H-NMR, FTIR, and GPC results. Initiation, propagation, and termination mechanisms were discussed based on the structural analysis of the polyacetal polyols. The results of GPC, NMR, and IR measurements showed that the PDOP triols obtained had similar branch chain lengths. Number-average molecular weights were determined by vapor pressure osmometry (VPO), end group titration and 1 H-NMR.

New oxocarbenium perchlorates, [(C2H5)(4-n)C(CH2OCH2CH2CO+ClO)n, n = 3, 4] were synthesized and used in the preparation of poly (tetrahydrofuran) (PTHF) polyols. The structures of PTHF polyols and corresponding hydrolysis products were determined by 1H-NMR and FTIR. GPC curves showed that the amount of cyclic oligomers was negligible. The polymerization process was followed by gas chromatography. Kinetic studies showed no termination reaction. The mechanism of the polymerization was discussed. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 3391–3399, 1999

A new four-armed poly(1,3-dioxepane) tetraol was prepared by cationic ring-opening polymerization of 1,3-dioxepane (DOP) in the presence of 6,6-bis(5-hydroxyl-2-oxapentyl)-4,8-dioxaundecanediol1,11 (THA) with triflic acid(I) as initiator. The structure of the poly(DOP) tetraol obtained was characterized by 1 H and 13 C NMR spectra. The molecular weights of the obtained tetraols were controlled by the mole ratio of DOP consumed to initial THA, and it was found that each macromolecule contains only one THA unit on the average. GPC studies showed that the cyclic oligomers in the products were negligible.

Starting from a bio-based polyol through modification of soybean oil, BIOH™ X-210, two series of bio-based polyurethanes-clay nanocomposite foams have been prepared. The effects of organically-modified clay types and loadings on foam morphology, cell structure, and the mechanical and thermal properties of these bio-based polyurethanes-clay nanocomposite foams have been studied with optical microscopy, compression test, thermal conductivity, DMA and TGA characterization. Density of nanocomposite foams decreases with the increase of clay loadings, while reduced 10% compressive stress and yield stress keep constant up to 2.5% clay loading in polyol. The friability of rigid polyurethane-clay nanocomposite foams is high than that of foam without clay, and the friability for nanofoams from Cloisite® 10A is higher than that from 30B at the same clay loadings. The incorporation of clay nanoplatelets decreases the cell size in nanocomposite foams, meanwhile increases the cell density; which would be helpful in terms of improving thermal insulation properties. All the nanocomposite foams were characterized by increased closed cell content compared with the control foam from X-210 without clay, suggesting the potential to improve thermal insulation of rigid polyurethane foams by utilizing organically modified clay. Incorporation of clay into rigid polyurethane foams results in the increase in glass transition temperature: the Tg increased from 186 to 197 to 204 °C when 30B concentration in X-210 increased from 0 to 0.5 to 2.5%, respectively. Even though the thermal conductivity of nanocomposite foams from 30B is lower than or equal to that of rigid polyurethane control foam from X-210, thermal conductivity of nanocomposite foams from 10A is higher than that of control at all 10A concentrations. The reason for this abnormal phenomenon is not clear at this moment; investigation on this is on progress.