Poly Ester Amide Research Articles

Synthesis and hydrolytic degradation of aliphatic polyesteramides branched by glycerol

A series of branched polyesteramides (PEAs) were synthesized from adipic acid, hexamethylene diamine, 1,4-butanediol and caprolactam by melt polycondensation using glycerol as branching agent. The obtained copolymers, with glycerol contents of 0–0.9 wt% (LPEA–PEAg10) were characterized by FTIR, 1H NMR, DSC and viscometry. The FTIR and 1H NMR spectra demonstrated the formation of ester and amide bonds. DSC data indicated the melting and crystallization temperatures decrease with increasing glycerol content. Water absorption experiments suggested no distinct difference in hydrophilicity between these branched PEAs. Alkaline hydrolysis of PEA films was conducted in pH 11.0 NaOH solution at 37, 50 or 80 °C, respectively. The tests showed that PEAs degraded quickly in alkali and the degradation rate increased with the medium temperature. PEA films underwent slow degradation in pH 7.0 phosphate buffer saline (PBS) at 37 °C. The degradation was monitored by weight loss, viscometry, DSC, FTIR and 1H NMR analysis. The results showed that branching substantially enhanced the degradation. Structural analyses revealed that ester/amide ratio decreased with incubation time, suggesting the degradation occurs mainly on the ester bonds. During the degradation, the melt temperature and crystallinity of the copolymers increased slightly with the degradation time.

Biodegradable Multiphase Systems Based on Plasticized Starch: A Review

The aim of this review is to show the relationships between the structure, the process, and the properties of biodegradable multiphase systems based on plasticized starch (PLS), the so‐called “thermoplastic starch.” These mutiphase materials are obtained when associating association between plasticized starches and other biodegradable materials, such as biodegradable polyesters [polycaprolactone (PCL), polyhydroxyalkanoates (PHAs), polylactic acid (PLA), polyesteramide (PEA), aliphatic, and aromatic copolyesters], or agro‐materials (ligno‐cellulosic fiber, lignin etc.). Depending on materials (soft, rigid) and the plastic processing system used, various structures (blends, composites, multilayers) can be obtained. The compatibility problematic between these hetero‐materials is analyzed. These starchy products show some interesting properties and have some applications in different fields: packaging, sports, catering, agriculture and gardening, or hygiene.

Interacting Blends of Novel Unsaturated Polyester Amide Resin with Methyl Methacrylate

Novel unsaturated poly (ester-amide) resins (UPEAs) were prepared by the reaction between an epoxy resin, namely diglycidyl ether of bisphenol–A (DGEBA) and unsaturated aliphatic bisamic acids, using a base catalyst. These UPEAs were then blended with a vinyl monomer namely, methyl methacrylate (MMA) to produce a homogeneous resin syrup. The curing of these UPEAs-MMA resin blends was carried out by using benzoyl peroxide (BPO) as a catalyst and was monitored by using a differential scanning calorimeter (DSC). The glass fibre reinforced composites (i.e. laminates) of this UPEA-MMA resin blends were fabricated using the DSC data. The chemical, mechanical and electrical properties of the glass fibre composites have also been evaluated. The unreinforced cured samples of the UPEA-MMA resin blends were also analysed by thermogravimetry (TGA).

Thermal properties of biaxially deformed in situ composites

AbstractThe thermal properties of biaxially blown poly(etherimide) (PEI) films containing a thermotropic liquid crystalline polymer (TLCP) were studied using differential scanning calorimetry, thermogravimetric analysis, wide‐angle X‐ray diffraction and dynamic mechanical thermal analysis. The effects of the compatibilizer and thermal annealing on the thermal properties of biaxially oriented TLCP films were investigated. Though the compatibilizer (poly(ester imide)) improved deformation of the TLCP phase (poly ester amide) and adhesion between the matrix and the TLCP phase, which improved mechanical properties, it did not significantly affect the thermal properties of the in situ composite films. The film degradation behavior corroborated the role of the compatibilizer. Since a relatively small amount of TLCP (10 wt%) was added to the matrix and the matrix PEI was amorphous, the effect of annealing on the TLCP structure was not obvious. By the same token, while the effect of the deformation in the circumferential direction (a change in the blow‐up ratio) was manifest in mechanical property improvements, its effect on the thermal properties was not obvious. All films showed similar thermal expansion behaviors, regardless of the thermal history and of the compatibilizer addition. Thus, there is an optimum amount of the compatibilizer required to obtain optimal mechanical properties for in situ composite films without causing a deterioration of their thermal properties. Polym. Eng. Sci. 44:1419–1428, 2004. © 2004 Society of Plastics Engineers.

Preparation of biodegradable polyesteramide microspheres

Biodegradable polyesteramide copolymer P(CL/AU) based on e-caprolactone and 11-aminoundecanoic acid was synthesized by the melt polycondensation method. Polyesteramide (PEA) microspheres were prepared by a simple O/W emulsion solvent evaporation method. The effects of variations in preparation parameters (such as emulsifier concentration, polymer concentration, polymer solution adding rate, stirring rate, and whether vacuum was applied) were studied in detail. The obtained microsphere morphologies were observed using an optical microscope and via scanning electron microscopy (SEM). The particle size distribution was determined using a Malvern laser particle sizer. When the PEA microspheres were incubated in PBS saline, the particle size increased at first, and then decreased after a longer time period; the theory that this behavior was due to degradation of the microspheres was confirmed by SEM.

Novel Unsaturated Polyester Amide Resins Based on Epoxy Resins

Novel unsaturated polyester amide resins (UPEAs) were prepared by the addition reaction of commercially available epoxy resin, namely diglycidyl ether synthesized from bisphenol-A and epichlorohydrin and having the molecular weight 340 with aromatic unsaturated bisamic acids. These UPEAs were characterized by elemental analysis and number average molecular weight determination by nonaqueous conductometric titrations. The curing study of these UPEAs was carried out by using benzoyl peroxide (BPO) as a catalyst and was monitored by using a differential scanning calorimeter (DSC). According to the curing temperature obtained from the DSC thermograms, the glass fiber reinforced composites (i.e., laminates) of these UPEA–BPO systems have been fabricated. The chemical, mechanical, and electrical properties of these glass fiber composites have also been evaluated. The unreinforced cured samples of the UPEA resins were also analyzed by using thermogravimetric analyzer (TGA).

Interacting Blends of Novel Unsaturated Polyester Amide Resin with Vinyl Acetate

Novel unsaturated poly (ester‐ amide) resins (UPEAs) were prepared by the reaction between an epoxy resin, namely diglycidyl ether of bisphenol–A (DGEBA) and unsaturated aliphatic bisamic acids using a base catalyst. These UPEAs were then blended with a vinyl monomer namely, Vinyl acetate (VA) to produce a homogeneous resin syrup. The curing of these UPEAs‐VA resin blends was carried out by using benzoyl peroxide (BPO) as an initiator for the radical polymerization and was monitored by using a differential scanning calorimeter (DSC). The glass fibre reinforced composites (i.e. laminates) of these UPEA‐VA resin blends were fabricated using the DSC data. The chemical, mechanical and electrical properties of the glass fibre composites have also been evaluated. The unreinforced cured samples of the UPEA‐VA resin blends were also analyzed by thermogravimetry (TGA).

Interacting Blends of Novel Unsaturated Polyester Amide Resin with Styrene

Novel unsaturated poly (ester‐amide) resins (UPEAs) were prepared by the reaction between an epoxy resin, namely diglycidyl ether of bisphenol–A (DGEBA) and unsaturated aliphatic bisamic acids using a base catalyst. These UPEAs were then blended with a vinyl monomer namely, Styrene (STY.) to produce a homogeneous resin syrup. The curing of these UPEAs‐STY. resin blends was carried out by using benzoyl peroxide (BPO) as a catalyst and was monitored by using a differential scanning calorimeter (DSC). The glass fibre reinforced composites (i.e. laminates) of these UPEA‐STY. resin blends were fabricated using the DSC data. The chemical, mechanical and electrical properties of the glass fibre composites have also been evaluated. The unreinforced cured samples of the UPEA‐STY. resin blends were also analyzed by thermogravimetry (TGA).

Catalytic polymerization of N,N-diethanol acrylamide with phthalic anhydride in the presence of H-mordenite and Fe-mordenite zeolites

Hmordenite zeolite was shown to be a recyclable catalyst for N , N -diethanol acrylamide (DEAA; 91% selectivity) with phthalic anhydride (PA) yielding polyesteramide (PEA, 100% selectivity) resin in only 30 min. The H-mordenite zeolite catalyzes the polymerization of N , N -diethanol acrylamide (DEAA) with phthalic anhydride (PA) yielding polyesteramide (PEA) resin. The Fe modified mordenites showed lower activity than that of H-mordenite that presented high stability on multiple recycling. The formation of DEAA; the principal step in forming PEA, was occurred through the condensation reaction of diethanol amine (DEA) and acrylic acid (AA) with 91% selectivity in addition to 9% devoted for the corresponding ester (diethanol amine monoacrylate; DEMA). The IR spectroscopic study of DEAA formation in the presence of mordenite zeolite reveals the greater affinity of the reactants specifically AA to protons that are likely to be the initiators of the DEAA formation. The formation of ester was confirmed through the appearance of a band at 1735 cm −1 attributed to the stretching vibration of CO of ester groups. A possible reaction mechanism is proposed based on data reported in the literature and the results of the present investigation. The activation energy of the DEAA formation was found to be 35.5 kJ mol −1 , for non-catalyzed and 11.46 kJ mol −1 , for the H-mordenite catalyzed one. The acidic and textural properties of the catalytic samples have been measured using NH 3 adsorption (at 150 °C) and N 2 adsorption (at −196 °C), respectively. The results obtained indicate the importance of the zeolite acid selectivity towards amide and ester formation.

Alkaline degradation behavior of polyesteramide fibers: surface erosion

In this work, a new kind of aliphatic polyesteramide (PEA) copolymer based on e-caprolactone and 6-aminocaproic acid was synthesized by the melt polycondensation method. Biodegradable PEA fibers were processed by the melt-spinning method. 1H-NMR, FTIR, SEM, and tensile testing were used to characterize the degradation of PEA fibers in concentrated alkaline solution. The PEA fiber undergoes surface erosion in such concentrated alkaline solutions.

Stabilization and mechanical properties of biodegradable aliphatic polyesteramide and its filled composites

The stabilization of polyesteramide (PEA) was studied by TGA, melt index and intrinsic viscosity. Primary antioxidant A1010 (0.6 wt.%) combined with 0.2 wt.% of hydroperoxide decomposer A168 is effective in stabilizing PEA; but the holding life of PEA in the extruder barrel is only 30 min, and the antioxidants are completely consumed when it is extruded four times. Fillers including heavy calcium carbonate (HCC), tricalcium phosphate (TCP) and talc affect both the thermal stability and mechanical properties of the resultant composites, which are discussed in detail. The Turcsanyi model can best describe the composition dependence of tensile strength of the HCC and talc filled PEA, and the Sato-Furukawa can best predict the Young's modulus of HCC filled PEA, but is poor for the talc-filled material

Studies on bamboo polymer composites with polyester amide polyol as interfacial agent

AbstractThe effect of surface treatment on the properties of bamboo/epoxy, bamboo/polyester composites was investigated. An improvement in the properties was observed when the surfaces of the bamboo fibers were modified with polyesteramide polyol (PEAP). The performance of surface treated bamboo composites in terms of water resistance is significantly better than that of untreated bamboo composites. Polyester amide polyol treated bamboo composites exhibited better mechanical strength properties. Fractographic evidence such as fiber breakage/splitting and matrix adherence on the pulled‐out fiber surface explains such behavior.

Hydrogen-bonded thermotropic liquid-crystalline polyester-amides from bis(hydroxy alkamido)aranes: Synthesis and properties

Hydrogen-bonded aromatic–aliphatic polyester–amides (PEAs) were prepared by solution/melt polycondensation of aromatic–aliphatic amidodiols 1,4-bis(4-hydroxybutyramide)benzene (BHBB), 1,4-bis(5-hydroxy pentamide)benzene, 1,4-bis(6-hydroxyhexamide)benzene, 1,4-bis(4-hydroxybutyramidexylene), 1,4-bis(5-hydroxypentamidexylene, 1,4-bis(4-hydroxybutyramide)benzene, and 1,4-bis(6-hydroxyhexamidexylene) with terephthaloyl chloride/dimethyl terephthalate. Aromatic–aliphatic amido diols were prepared by the aminolysis of γ-butyrolactone, δ-valerolactone, and ϵ-caprolactone with aromatic diamines such as paraphenylene diamine and paraxylene diamine. The monomers and polymers were characterized by chemical analysis (hydroxyl value and elemental analysis), Fourier transform infrared spectroscopy, 1H NMR, and 13C NMR. The thermal- and phase-transition behaviors of the polymers were investigated by differential scanning calorimetry in combination with hot-stage optical microscopy. Crystallinity of polymers was examined with wide-angle X-ray diffraction. The polymers exhibited liquid crystallinity with layered structures formed by self-organization of the hetero intermolecular hydrogen-bonded networks indicating smectic phases except for PEAs prepared from BHBB. The hydrogen atom of the phenyl-substituent group forces the neighboring carbonyl groups out of plane of the rings preventing formation of layered structures in the case of BHBB. The PEAs retained intermolecular hydrogen bonding even in the mesomorphic state, and variations in the hydrogen-bonded lamellae/micelles might be responsible for the variations from one smectic to another texture. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 335–346, 2003

Novel Eco-Friendly Biocomposites: Biofiber Reinforced Biodegradable Polyester Amide Composites—Fabrication and Properties Evaluation

Lignocellulosic natural fibers like sisal and pineapple leaf fiber (PALF) can be incorporated in polymers based on biodegradable polyester amide matrix, BAK 1095 for achieving desired properties and texture in the resulting biocomposites. But high level of moisture absorption, poor wettability and insufficient adhesion between untreated fiber and the polymer matrix led to debonding with age. In order to improve the above qualities, various surface treatments of sisal fiber like mercerization, cyanoethylation, acetylation, bleaching and vinyl monomer (acrylonitrile) grafting are carried out which results in improved mechanical performance of sisal-BAK composites. Mechanical properties like tensile and flexural strength are optimum at a fiber loading of 50 wt%. Among all modifications, alkali treatment and acetylation result in improved properties of the composites. Alkali treated sisal composite shows about 20% increase in tensile strength and acetylated sisal composite shows about 14% increase in flexural strength compared to the control, i.e., untreated sisal based biocomposites. From the biodegradation study, we find that after 60 days of soil burial about 1% weight loss is observed for BAK whereas acetylated sisal-BAK composite shows maximum weight loss (22%). It also shows maximum decrease in flexural strength (47%) after 15 days of sisal burial. A comparative account of properties of PALF-BAK and sisal-BAK biocomposites is also given. Scanning electron microscopic studies were carried out for better understanding of fiber-matrix adhesion in biocomposites.

Novel eco‐friendly biodegradable coir‐polyester amide biocomposites: Fabrication and properties evaluation

AbstractBiocomposites are prepared from a cheap, renewable natural fiber, coir (coconut fiber) as reinforcement with a biodegradable polyester amide (BAK 1095) matrix. In order to have better fiber‐matrix interaction the fibers are surface modified through alkali treatment, cyanoethylation, bleaching and vinyl grafting. The effects of different fiber surface treatments and fiber amounts on the performance of resulting bio‐composites are investigated. Among all modifications, cyanoethylated coir‐BAK composites show better tensile strength (35.50 MPa) whereas 7% methyl methacrylate grafted coir‐BAK composites show significant improvement in flexural strength (87.36 MPa). The remarkable achievement of the present investigation is that a low strength coir fiber, through optimal surface modifications, on reinforcement with BAK show an encouraging level of mechanical properties. Moreover, the elongation at break of BAK polymer is considerably reduced by the incorporation of coir fibers from nearly 400% (percent elongation of pure BAK) to 16‐24% (coir‐BAK biocomposites). SEM investigations show that surface modifications improve the fiber‐matrix adhesion. From biodegradation studies we find that after 52 days of soil burial, alkali treated and bleached coir‐BAK composites show significant weight loss. More than 70% decrease in flexural strength is observed for alkali treated coir‐BAK composites after 35 days of soil burial. The loss of weight and the decrease of flexural strength of degraded composites are more or less directly related.

Properties of Biodegradable Multilayer Films Based on Plasticized Wheat Starch

Multilayer films based on plasticized wheat starch (PWS) and various biodegradable aliphatic polyesters have been prepared through flat film coextrusion and compression molding. Poly(lactic acid) (PLA), polyesteramide (PEA), poly(μ-caprolactone) (PCL), poly(butylene succinate adipate) (PBSA), and poly(hydroxybutyrate-co-valerate) (PHBV) were chosen as the outer layers of the stratified "polyester/PWS/polyester" film structure. The main goal of the polyester layers was to improve significantly the properties of PWS in terms of mechanical performance and moisture resistance. Since no specific compatibilizer or tie layer were added, the properties of subsequent films rely on the compatibility between the respective materials only. The effects of glycerol content in PWS, polyester type, and film composition on the mechanical properties and adhesion strength of multilayers were investigated. The conditions for optimal product performance were examined. The multilayer films may be suitable for applications in food packaging or disposable articles.

Association between plasticized starch and polyesters: Processing and performances of injected biodegradable systems

AbstractDifferent formulations of wheat thermoplastic starch (TPS) have been processed with various plasticizer/starch ratios and moisture contents. The biodegradable polyesters tested are polycaprolactone (PCL), polyester amide (PEA), polybutylene succinate adipate (PBSA) and polybutylene adipate co terephtalate (PBAT). TPS and polyesters are melt blended in different proportions by extrusion and then injected to obtain dumbbell specimens. Various properties are evaluated such as the mechanical properties (tensile and impact tests), and the hydrophilic character with contact angle measurements. Additionally, uniaxial shrinkage is evaluated. Results show that the addition of polyester to TPS increases the dimensional post‐injection stability. Blend modulus values are close to the results of the classical rule of mixture. Elongation at break, resilience values and SEM observations seem to give some indications about the compatibility between both polymeric systems. PBAT and PEA present better results than PCL and PBSA. Contact angle measurement show that we have a drastic increase of the hydrophobic character from 10% of polyester in the blend. The different combinations of TPS and polyesters give a wide range of mechanical behavior for compostable materials, to be developed in specific applications.

Studies on blends of melt-processable liquid crystalline polymers and thermoplastics. I. Blend of polyesteramide with polyethylene

The processability characteristics, physicomechanical properties, and thermal decomposition characteristics of blends of low-density polyethylene (LDPE) and polyesteramide (PEA), a thermotropic liquid crystalline polymer, were studied using various analytical techniques. Studies on a Brabender Plasticorder at temperatures ranging from 170 to 230°C showed good melt processability for the blends. The melt rheology of the blends containing 0–15% of PEA at 170°C was studied using a capillary rheometer (Goettfert) fitted with a circular die (L/D = 30/1) at apparent shear rates ranging from 12 to 2300 s−1. The samples containing PEA showed a comparatively lower die swell at high shear rates. X-ray diffraction measurements showed a reduction in crystallinity of LDPE in the presence of 2–4% of PEA. Scanning electron microscopic evaluation of the morphology of the fractured surface of the blend showed some degree of orientation, but not to the level typical of LCPs. However, differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) indicated significant improvement in the resistance to thermooxidative decomposition of LDPE modified with PEA. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 78: 1811–1817, 2000

Carboxyl terminated polyamide 12 chain extension by reactive extrusion using a dioxazoline coupling agent. Part I: Extrusion parameters analysis

AbstractCondensation reaction between a carboxyl terminated polyamide 12 (CTPA) (Mn = 2000 g mol−1) and a dioxazoline [2,2′‐(1,3‐phenylene)‐bis(2‐oxazoline)] (OO) was achieved by reactive extrusion. Extrusion parameters effects on the process were analyzed through residence time distribution (RTD) and conversion distribution (CD) evolutions. RTD was measured using ultraviolet and ultrasonic detectable tracers. RTD measured along the extruder screws showed a decrease of the dimensionless variance (σ) with the reaction progress. Comparing measured molar masses and dispersity with those calculated using CD, competition between condensation and chain scission was detected. Effects of barrel temperature, screw profile, rotation speed and viscous dissipation on the reactive system evolution were analyzed and used for the process optimization. It was shown that a polyester amide with a Dpn 12 can be obtained using this dioxazoline coupling agent by reactive extrusion.

Degradation Kinetics of Biodegradable Fiber Composites

In a composite, fast degradable fibers determine the degradation of the slowly degradable matrix. Such biodegradable composites consisting of degummed hemp fibers and a polyester amide matrix were produced with fiber mass fractions between 0 and 0.48. The hot-pressed plates, 1-mm thick, were incubated in a standard soil. The degradation kinetics was quantified by the measurement of CO2 production. Furthermore, after termination of experiment, the carbon balance was uncovered. The results were fitted to an exponential law taking into account the degradation of fibers. The increased amount of pores realized by high fiber contents induces pronounced degradation. The degradation is fully characterized by the time constant t, which is correlated to the fiber mass fraction. The model allows to predict the degradation kinetics of composites with a few well-defined experiments.