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Polylactide (PLA) composites with acrylic impact modifier BPM, i.e., PLA/BPM composites, were produced by the melt blending method. The effects of BPM on the thermal properties, melting behaviors, and dynamic mechanical properties of the PLA/BPMs were investigated by thermogravimetric analysis, differential scanning calorimetry, and dynamic mechanical analysis. Tensile strength, flexural strength, and modulus of the injection molded specimens were measured by an Instron tensile machine. The influence of BPM on the impact strength of injection molded PLA/BPM composites was examined using an impact tester. The morphology of cryofractured surfaces and fracture surfaces of the composites after the tensile and impact testing was also investigated using scanning electron microscope. The test results show that the composites with BPM possess better flexibility when compared with neat PLA. However, the notched Izod impact strength showed improvement only when the BPM content was higher than 15 wt%.

A series of novel branched polyester-based ionomers were synthesized with trihydroxy ethyl esters of trimethyl-1,3,5-benzentricarboxylate (as branching agent) and sodium salt of 2-hydroxyethyl 3-(phenylphosphinyl)propionate (SHPPP, as end-capping agent) by melt polycondensation. The chemical structures of the branched polyester-based ionomers were confirmed with 1H and 31P NMR spectra. The effects of branching and ionic end groups on the melt behavior and thermal properties were investigated by differential scanning calorimetry and thermogravimetric analysis. The flammability and fire behavior were characterized by limiting oxygen index (LOI) and cone calorimeter. The LOI values of branched poly(ethylene terephthalate)s (PETs) are higher than that of pure PET. The cone calorimeter parameters of the samples such as heat release rate, total heat release, and time to ignition indicate that the fire safety of branched polyester-based ionomers is improved by introducing SHPPP. The effects of SHPPP on accelerat...

Poly(p‐dioxanone) (PPDO)/hydroxyapatite (HA) composites with high viscosity‐average molecular weights (say, 343,000 g/mol) were prepared through the in situ ring‐opening polymerization of p‐dioxanone (PDO) with HA nanopaticles (n‐HA) and organically modified HA (EG‐HA) in the presence of triethylaluminum as the catalyst. The structures of n‐HA and EG‐HA synthesized were characterized by Fourier transform infrared spectroscopy and powder X‐ray diffractometer. Scanning electron microscopy and transmission electron microscopy were used to observe the dispersibility and morphology of nanopaticles in the PPDO matrix and the ethanol solution, respectively. The thermal properties were examined with differential scanning calorimeter and thermogravimetric analyzer. In conclusion, the PPDO/EG‐HA composites have better thermal stability and higher overall crystallization rate than both the PPDO/HA composites and the neat PPDO. A nucleating effect of n‐HA was observed as the crystallization temperature of PPDO increased.

BACKGROUND: The increasing uses of non-woven fabrics need the development of a kind of novel flame-retardant polyester with low melting temperature. Neopentyl glycol (NPG) and 3-(hydroxyphenylphosphinyl)propionic acid (HPPPA) were used as the third and fourth comonomer to synthesize phosphorus-containing poly[(ethylene terephthalate)-co-(neopentyl terephthalate)] (PENT) with both flame retardancy and low melting temperature. RESULTS: The chemical structure of PENT was confirmed using Fourier transform infrared, 1H NMR, 13C NMR and 31P NMR spectroscopy. PENT displays a monomodal gel permeation chromatography curve. When the content of NPG was kept at 10 wt% and the content of HPPPA increased to 5 wt%, the melting temperature (Tm) of the resulting PENT5/10 decreases to 171.2 °C, a 34.6 °C decrease compared to that of PENT0/10 (containing no HPPPA). The flammability of the PENTs was characterized with the limiting oxygen index (LOI) test, the UL-94 vertical test and the cone calorimeter test. The incorporation of HPPPA can significantly improve the flame retardancy of the PENTs, the LOI values of the PENTs increasing from 24.4 to 37.6, as the loading of HPPPA increases from 0 to 5 wt%. CONCLUSION: The PENTs possess both low melting temperatures and excellent flame retardancy. HPPPA can be used as fourth comonomer to improve the flame retardancy of the PENTs, while decreasing the Tm value of the copolyester. Copyright © 2009 Society of Chemical Industry

In order to obtain poly(ethylene terephthalate) (PET) engineering plastics with good flame retardancy, heat resistance, and mechanical properties, a novel phosphorus-containing copolyester (PET-co-DDP)/organo-montmorillonite (OMMT 1%) nanocomposite (PET-co-DDP/OMMT) was prepared by in situ intercalating polymerization. Nonisothermal crystallization kinetics and nanoscale morphology of this composite have been investigated by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and differential scanning calorimetry (DSC). Based on the results of the nonisothermal crystallization kinetics, the flame-retardant copolyester PET-co-DDP has a lower crystallization rate than pure PET, while PET-co-DDP/OMMT nanocomposite has a higher crystallization rate than pure PET. Based on the Augis and Bennett method, the activation energies for nonisothermal crystallization of pure PET, PET-co-DDP, and PET-co-DDP/OMMT nanocomposite were evaluated as 101, 138, and 76 kJ mol−1, respectively. All the evi...

Polyethylene (PE) was treated with various formulations containing an intumescent fire retardant, which consists of melamine phosphate (MP), pentaerythritol (PER) and ammonium polyphosphate (APP), and one or none of following metal chelates: CuSAO, CoSAO and NiSAO. The behaviour of this intumescent system can be enhanced significantly by the addition of small amounts (0.2%) of metal chelate (CuSAO, CoSAO and NiSAO). The thermal stabilization, burning behaviour and char formation of the fire retardant PE system have been investigated by TGA, LOI, UL-94 test, SEM and cone calorimetry. All formulations studied provide good fire retardant behaviour, with LOI ≥ 27.4 and UL-94 V-0 rating. TGA results present more complicated thermal decomposition behaviour after the addition of small amounts (0.2%) of metal chelate when compared to that of PE-IFR. Cone calorimetry of PE-IFR–metal chelate (PE-IFR–CuSAO, PE-IFR–CoSAO and PE-IFR–NiSAO) shows a very significant decrease in HRR, PHRR, ML, THR and a very significant improvement of TTI compared to samples without metal chelate. Furthermore, SEM and photographs of the char layer show that the char layer from PE-IFR–metal chelate has a compact and tough char structure compared to the open porous char layer produced by sample without metal chelate.

An attractive intumescent flame retardant epoxy system was prepared from epoxy resin (diglycidyl ether of bisphenol A), low molecular weight polyamide (cure agent, LWPA), and ammonium polyphosphate (APP). The cured epoxy resin was served as carbonization agent as well as blowing agent itself in the intumescent flame retardant formulation. Flammability and thermal stability of the cured epoxy resins with different contents of APP and LWPA were investigated by limited oxygen index (LOI), UL-94 test, and thermogravimetric analysis (TGA). The results of LOI and UL-94 indicate that APP can improve the flame retardancy of LWPA-cured epoxy resins. Only 5 wt % of APP can increase the LOI value of epoxy resins from 19.6 to 27.1, and improve the UL-94 ratings, reaching V-0 rating from no rating when the mass ratio of epoxy resin to LWPA is 100/40. It is much interesting that LOI values of flame retardant cured epoxy resins (FR-CEP) increase with decreasing LWPA. The results of TGA, FTIR, and X-ray photoelectron spectroscopy (XPS) indicate that the process of thermal degradation of FR-CEP consists of two main stages: the first stage is that a phosphorus rich char is formed on the surface of the material under 500°C, and then a compact char yields over 500°C; the second stage is that the char residue layer can give more effective protection for the materials than the char formed at the first stage do. The flame retardant mechanism also has been discussed according to the results of TGA, FTIR, and XPS for FR-CEP. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008

The ionomer concept was introduced to the field of flame-retardant polyesters for the first time. The ionic monomer, sodium salt of 2-hydroxyethyl 3-(phenylphosphinyl)propionate (SHPPP), was synthesized by selective esterification of 3-(hydroxyphenylphosphinyl)propionic acid with ethylene glycol, followed by neutralization with sodium carbonate anhydrous. SHPPP was characterized with 1H, 13C, and 31P NMR spectroscopy, Fourier transform infrared spectroscopy, and X-Ray photoelectron spectroscopy. Poly(ethylene terephthalate)-based ionomers containing terminal units derived from this ionic monomer, were synthesized by melt polycondensation. The chemical structure of the ionomers was characterized with 1H, 13C, and 31P NMR spectroscopy. The effects of SHPPP on the thermal properties and melting behaviors of the ionomers were investigated by thermogravimetric analysis and differential scanning calorimetry. The flammability of the ionomers was characterized by the limiting oxygen index test. The test results show that the ionomers themselves possess both excellent flame retardancy and antidripping properties. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 2994–3006, 2008

To address the problem of formaldehyde-free flame retardation of wood particleboard, a novel phosphorus-containing compound, di(2,2-dimethyl-1,3-propanediol phosphate) urea (DDPPU) was synthesized. DDPPU was used as flame retardant for wood particleboard. The flammability of treated wood particleboard systems consisted of wood particles, polyurethane (PU) adhesive, and different flame retardant formulations were investigated by limiting oxygen index (LOI). The results of LOI indicate that DDPPU could improve the flame retardancy of wood particleboard. However, when H3BO3 was used as the second flame retardant component and combined with DDPPU, the flame retardant wood particleboard could obtain the highest LOI value (46.0) in these experiments. Thermogravimetric analysis shows that treated wood particleboard can decrease the initial decomposition temperature, and that at higher temperatures the degradation rate are lower than the untreated wood particleboard. Furthermore, wood particleboard treated with DDPPU/H3BO3 has a higher yield of residue char at 600°C than that treated with other flame retardant systems. The ability of char formation of these samples agrees with the order of LOI values. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008

Summary: It is a big challenge to improve simultaneously both the flame retardancy and the melt-dripping resistance of polymeric materials such as PET. In this paper, a novel intumescent flame retardant, DPSPB, was synthesized and blended with copolyester PET-co-DDP/O-MMT nanocomposites, which were synthesized by polycondensation of TPA, EG, DDP, and O-MMT. The resulting PET-co-DDP/O-MMT/DPSPB nanocomposites exhibit very good flame retardance and dripping resistance, e.g., LOI = 29, UL-94 V-0. SEM, XRD, and XPS were used to investigate the relationships between the structures and properties of the composites. It is proved that DPSPB offers excellent protection for the structure of nanocomposites, which is responsible for the good anti-dripping properties of the nanocomposites. Residues of copolyesters after combustion: common nanocomposite residue of PDMN (left) and the novel nanocomposite residue of PDMN/DPSPB (right).

A novel phosphorus-containing copolyester (PET-co-DDP)/barium sulfate (BaSO4) nanocomposite was synthesized by in situ polymerization. The oxygen index values of the resulting nanocomposites decreased with increasing the content of BaSO4 nanoparticles, but their antidripping behaviors were improved obviously through the UL-94 test. The flammability tests based on the cone calorimetry showed that the introduction of nano-BaSO4 to the copolyester decreased remarkably the heat release rate and effective heat of combustion. The thermal oxidative decomposition behaviors of PET-co-DDP/BaSO4 nanocomposites were studied by a conventional dynamic thermogravimetric analysis in a flowing air atmosphere with a heating rate of 20°C/min. The activation energies determined from Kissinger method, Flynn-Wall-Ozawa method, and Friedman method had a same variation trend. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 564–570, 2006

We developed a novel method for preparing poly(ethylene terephthalate)/BaSO4 nanocomposites, which were synthesized by in situ polymerization of terephthalic acid (TPA), ethylene glycol (EG) and BaSO4 nanoparticles prepared by reacting H2SO4 with Ba(OH)2 in ethylene glycol (EG). It was shown that the addition of BaSO4 would not influence the synthesis of PET. The structure of the nanocomposites was characterized by transmission electron microscopy (TEM), and the nanoscale dispersion of BaSO4 particles in the PET matrix was observed when the BaSO4 content is below 4 wt%. Moreover, the thermal properties of the nanocomposites were investigated by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The results suggest that the degree of dispersion of BaSO4 particles in the PET matrix has important effect on the thermal properties of the nanocomposites. The existence of BaSO4 nanoparticles enhances the crystallization rate of PET. Besides, it was found that the thermal stability of PET was improved by the addition of the BaSO4 nanoparticles.

A novel one-step synthetic route, the double in situ approach, is used to produce both TiO2nanoparticles and polymer (PET), and simultaneously forming a nanocomposite with multi-functionality. The method uses the release of water during esterification to hydrolyze titanium (IV) butoxide (Ti(OBu)4) forming nano-TiO2in the polymerization vessel. This new approach is of general significance in the preparation of polymer nanocomposites, and will lead to a new route in the synthesis of multi-functional polymer nanocomposites.

In this manuscript, contradiction between the non-flammability and non-dripping of polyesters could be solved by copolymerizing terephthalic acid and ethylene glycol together with a pendent phenylethynyl-based monomer named 4-(phenylethynyl) di(ethylene glycol) phthalate (PEPE), which exhibited a cross-linkable nature at a proper temperature. TG-DSC simultaneous thermal analysis, FTIR, dissolution tests and rheological investigations proved the thermal cross-linking behavior of the copolyester, which was not active at the temperature of polymerization and processing but could cross-link rapidly at higher temperature before burning. LOI tests, cone calorimetry and small-scale flame tests further confirmed the self-extinguishment and inhibition for melt-dripping could be achieved through the cross-linking during burning, despite the absence of any flame-retardant element (say, bromine, chlorine, phosphorus, or nitrogen, etc.). Rheological analyses and the SEM microphotographs of the char showed P(ET-co-P)s exhibited a greater complex viscosity through the cross-linking at high temperature, leading to compact char residue, flame-retardant and anti-dripping effects.