Dynamic mechanical spectra of poly(itaconic acid esters) containing phenyl and cyclohexyl rings

The dynamic mechanical response of a series of poly(itaconic acid esters), in which the ester group, ---COOR, has R = (CH₂)_n ø with n = 0, 1, 2 and ø is either a phenyl or cyclohexyl ring, was studied over the temperature range 90 to 425K. In each case the glass transition temperature T_g, of the cyclohexyl derivative is higher than the corresponding phenyl derivative, and T_g also decreases as n increases. A β-transition, located in both the phenyl and cyclohexyl series, is attributed to motion of the ester groups. In addition the cyclohexyl polymers exhibit a prominant γ-transition caused by cyclohexyl ring movement and there is also a δ-transition in this series which is believed to be a precursor of the γ-transition.     

The synthesis and characterization of poly(itaconic) acid

Summary Poly(itaconic acid) (PIA) was obtained indirectly, by the hydrolysis of PIA esters and directly by the polymerization of itaconic acid in water or methanol at 30°C. The first method was not satisfactory but the second gave better results. The elemental composition of the synthetized samples deviated very little from the calculated values. Several crude polymers were fractionated in methanol/isopropanol and the fractions characterized by viscosity and light scattering. The statistically calculated LVN/M_W relation, valid for the undissociated polymer, was treated according to the method of Stockmayer and Kurata, to calculate the unperturbed dimensions and to compare them with those of other polymers.     

Interpolymeric complexes of poly(itaconic acid) and chitosan

Summary Polycomplexes of poly(itaconic acid) have been synthesized in the presence of small amounts of chitosan (eq. NH₂/eq. COOH between 0 and 1.31%). We have studied the effect on the yield and polydispersity of the final materials when increasing quantities of chitosan are employed. Under the reported experimental conditions, we have found that chitosan is quantitatively incorporated into the new material to produce dramatic effects on the system behavior. It has been established a critical R-value beyond which a hidrogel is obtained. The electrostatic interactions between polyelectrolytes turn from irreversible to reversible when pH is made strongly basic. Received: 1 April 2002 / Accepted: 3 May 2002     

Synthesis and characterization of complexes between poly(itaconic acid) and poly(ethylene glycol)

Summary Interpolymer complexes of poly(itaconic acid) and poly(ethylene glycol) (PIA/PEG) were prepared by two different procedures: simple mixing of preformed PIA and PEG and by polymerization of itaconic acid on poly(ethylene glycol) as a template. Complex formation was attributed to hydrogen bond formation between the carboxyl group of PIA and the ether group of PEG. The two types of complexes were characterized by viscometric measurements, thermogravimetric analysis (TGA), Fourier-transform infrared (FTIR) spectroscopy and adhesive force measurements. The results indicate that complexes prepared by template polymerization have a stronger hydrogen bonding and hence more ordered structure and better mucoadhesive properties.     

Crystallization of itaconic anhydride grafted poly(lactic acid) during annealing

The effect of annealing poly(lactic acid) (PLA) and PLA grafted with itaconic anhydride (IA) at different temperatures was studied using differential scanning calorimetry (DSC) and wide angle X‐ray scattering (WAXS). For PLA, two crystal forms were obtained when annealed between 110 and 120 °C, transforming into only the α‐form at 130 °C while a mixture of α′ and α‐form were obtained in grafted PLA. Grafting increased the percentage crystallinity of PLA, but it was mostly unaffected by the degree of grafting. The rate of crystallization was strongly dependent on the degree of grafting; when annealed at 100 °C, the crystallinity increased from 27.7 to 43.1% while the crystallization halftime reduced from 10.7 to 4.4 min at the lowest degree of grafting. It was thought that the increase in crystallization rate was likely due heterogeneous nucleation in the presence of grafted chains. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44614.     

Crosslinking cotton with poly(itaconic acid) and in situ polymerization of itaconic acid: Fabric mechanical strength retention

Polycarboxylic acids have been used as nonformaldehyde durable press finishing agents for cotton fabrics. Previously, we found that itaconic acid (IA) polymerized in situ on cotton fabric and also in an aqueous solution in the presence of a K₂S₂O₈/NaH₂PO₂ initiation system. Both poly(itaconic acid) (PIA) and the polymer formed by in situ polymerization of IA are able to crosslink cotton cellulose, thus imparting wrinkle resistance to cotton. In this research, we compared the performance of the cotton fabric crosslinked by PIA and that crosslinked by in situ polymerization of IA. The fabric treated with PIA and that treated with IA had similar wrinkle recovery angles. The cotton fabric treated with IA, however, lost more tensile strength than that treated with PIA due to cellulose degradation. We determined the magnitude of the fabric tensile strength loss attributed to crosslinking by separating the tensile strength loss due to cellulose degradation from the total tensile strength loss, and found that the tensile strength loss caused by crosslinking for the fabric treated with PIA was significantly higher than that for the fabric treated with IA. This can probably be attributed to more concentrated crosslinkages formed on the near surface of the PIA‐treated cotton fabric. PIA had poorer penetration into the amorphous cellulose region in fiber interior due to its much larger molecular size, thus increasing its concentration on the fabric's near surface. The data also suggest that more concentrated crosslinkages on the fabric surface reduced fabric abrasion resistance. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 87: 2023–2030, 2003     

Ultraviolet irradiation of poly(alkyl acrylates) and poly(alkyl methacrylates)

Acrylic and methacrylic homopolymers containing different side groups were irradiated with ultraviolet light in the presence of air. The changes of molecular weight distributions of the irradiated polymers were analyzed by means of gel permeation chromatography (GPC), and the rates of chain scission and crosslinking were estimated. As the result of this study, it was found that chain scission takes place more easily in polyalkyl methacrylates than in polyalkyl acrylates.     

Interactions between poly(acrylamide)–poly(itaconic acid) and cerium(IV)–nitrilotriacetic acid redox pair in the synthesis of acrylamide and itaconic acid homo‐ and copolymers

Homopolymers of itaconic acid (PIA) and its copolymers with acrylamide (P(IA‐AAm) were synthesized using ceric ammonium nitrate (NH₄)₂Ce(NO₃)₆ in combination with nitrilotriacetic acid (NTA) as redox initiator, and potassium persulphate at pH 1. The chain structures of the resulting products have been studied by FTIR spectroscopy. It is concluded from a comparison of spectroscopic results with gravimetric and viscometric data that the depressions in the yields and viscosity numbers in the case of Ce(IV)–NTA redox pair result from interactions between the constituents of the redox initiator and IA. Spectra of the insoluble and pale yellow precipitates, which are formed during the first 4 h of the reaction, after addition of Ce(IV) solution to the NTA and NTA–IA homogeneous solutions, also indicate the presence of various oxidation products. Furthermore, it is observed that H‐bonded homopolymer complex obtained from PAAm–PIA blends, prepared from aqueous solutions containing equal unit moles of each polymer, contain both ordered and defective structures. © 2001 Society of Chemical Industry     

An investigation of melt rheology and thermal stability of poly(lactic acid)/ poly(butylene succinate) nanocomposites

A systematic investigation of the rheological and thermal properties of nanocomposites prepared with poly(lactic acid) (PLA), poly(butylene succinate) (PBS), and organically modified layered silicate was carried out. PLA/PBS/Cloisite 30BX (organically modified MMT) clay nanocomposites were prepared by using simple melt extrusion process. Composition of PLA and PBS polymers were fixed at a ratio of 80 to 20 by wt % for all the nanocomposites. Rheological investigations showed that high clay (> 3 wt %) contents strongly improved the viscoelastic behavior of the nanocomposites. Percolation threshold region was attained between 3 and 5 wt % of clay loadings. With the addition of clay content for these nanocomposites, liquid‐like behavior of PLA/PBS blend gradually changed to solid‐like behavior as shown by dynamic rheology. Steady shear showed that shear viscosity for the nanocomposites decreased with increasing shear rates, exhibiting shear‐thinning non‐Newtonian behavior. At higher clay concentrations, pseudo‐plastic behavior was dominant, whereas pure blend showed almost Newtonian behavior. Thermogravimetric analysis revealed that both initial degradation temperature (at a 2% weight loss) and activation energy of thermal decomposition nanocomposite containing 3 wt % of C30BX were superior to those of other nanocomposites as well as to those of PLA/PBS blend. Nanocomposite having 1 wt % of C30BX did not achieve expected level of thermal stability due to the thermal instability of the surfactant present in the organoclay. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Poly(mono n-alkyl itaconic acid esters): Their preparation and some physical properties

A series of poly(mono n-alkyl itaconic acid esters), with ester chain lengths varying from methyl to decyl, were prepared by emulsion polymerisation. The materials are all hard brittle glassy polymers at ambient temperatures and undergo a dehydration reaction in the range 430 K to 450 K. Dynamic mechanical measurements showed the presence of at least three other damping maxima: an Δ-transition at 90?95 K, a δ-transition at 190–200 K and a γ-transition at 240–260 K. The ε is associated with motion in the hydrocarbon part of the side chain, while the δ and γ transitions are associated with relaxations involving the carboxyl and alkoxycarbonyl groups respectively. Glass transitions were only detectable in higher esters. The thermal stability of the polymers is also briefly discussed.     

Citrate esters as plasticizers for poly(lactic acid)

Citrate esters were used as plasticizers with poly(lactic acid) (PLA). Films were extruded using a single-screw extruder with plasticizer contents of 10, 20, and 30% by weight. All of the citrate esters investigated were found to be effective in reducing the glass transition temperature and improving the elongation at break. It was observed that the plasticizing efficiency was higher for the intermediate-molecular-weight plasticizers. Hydrolytic and enzymatic degradation tests were conducted on these films. It was found that the lower-molecular-weight citrates increased the enzymatic degradation rate of PLA and the higher-molecular-weight citrates decreased the degradation rate as compared with that of unplasticized PLA. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 66: 1507–1513, 1997     

The thermal stability of radiation-grafted poly(vinyl chlorides)

The thermal Stability of radiation-grafted poly(vinyl chloride) (PVC) has been investigated by thermogravimetric analysis and compared with the thermal stability of the corresponding PVC polymer blends. Although both the grafting of methyl methacrylate and styrene and the blending of the corresponding homopolymers yield products of improved thermal stability as compared with unmodified PVC, the radiation grafting is somewhat more efficient for the stabilization of PVC than blending. Further, the rate of dehydrochlorination of PVC–g–styrene at relatively high temperatures exhibits a retardation, whereas that of unirradiated PVC show significant acceleration. A detailed study about a series of PVC–g–styrenes polymerized under various conditions shows that the retardation effect is more noticeable in the samples irradiated to 2.0–3.0 Mrad than in those irradiated to less than 1.0 Mrad. From the dose dependency, it has been suggested that the retardation effect is due to the interruption of the propagation of dehydrochlorination by branch sites produced by the radiation process. On the other hand, the graft copolymers of vinyl pyridines, PVC-poly(vinyl pyridine), and PVC irradiated in the presence of pyridine are much less stable than unmodified PVC. The instability is explained in terms of the substitution reaction with the bases and the base-catalyzed dehydrochlorination of PVC.     

聚酯热稳定性的研究

在合成聚酯试验之后,利用聚合试验装置搅拌器扭矩变化来表征聚酯加工过程中的热稳定性,比热失重法更接近聚酯加工过程,比粘度降法减少了干扰因素。研究结果表明:稳定剂种类、添加量和调配方式等均影响聚酯的热稳定性。     

The thermal stability of some poly(di-aryl itaconates)

Summary The non-oxidative thermal stability of poly(di-aryl itaconates) was established by thermogravimetric analysis. The polymers investigated were poly(diphenyl itaconate) (PDPhI), poly(di-ortho-, meta- and para-tolyl itaconates) (PDoTI, PDmTI, PDpTI) and poly(dibenzyl itaconate) (PDBzI). The shapes of the DTG curves indicated that at least two reactions were involved in the degradation mechanisms. Carbonaceous residues were registered in all polymers. Preliminary thermal degradation experiments showed that the polymers decomposed mainly by depolymerisation with side chain scission registered in the cases of PDoTI and PDBzI. All polymers except PDBzI crosslinked slightly at lower degradation temperatures.     

Some factors affecting the stability of poly(carbamoyl sulfonates)

The low stability (both to evaporative concentration and to storage) of polymers terminated with aminooxomethanesulfonate groups (carbamoyl sulfonates) has been investigated. This low stability was induced by spontaneous changes in solution pH. These changes were produced by one of the two alternative reactions: loss of SO₂ which caused an increase in pH, and oxidation of the free bisulfite which decreased the pH. In this work, excess hydrogen peroxide was found to be the best stabilizer of poly(carbamoyl sulfonates). The optimum stability of poly(carbamoyl sulfonate) solutions was found to occur at pH 2–3 in aqueous ethanol.     

Determination of swelling behavior and morphological properties of poly(acrylamide‐co‐itaconic acid) and poly(acrylic acid‐co‐itaconic acid) copolymeric hydrogels

Poly(acrylamide‐co‐itaconic acid) (PAAmIA) and poly(acrylic acid‐co‐itaconic acid) (PAAIA) copolymeric hydrogels were prepared with different compositions via free‐radical polymerization. Ethylene glycol dimethacrylate (EGDMA) was used as an original crosslinker for these monomers. Gelation percentages of the monomers were studied in detail and it was found that addition of IA into the monomer mixture decreased the gelation percentage. The variation in swelling values (%) with time, temperature, and pH was determined for all hydrogels. PAA, which is the most swollen hydrogel, has the swelling percentage value of 2000% at pH = 7.4, 37°C. Swelling behaviors were explained with detailed SEM micrographs, which show the morphologic differences between dry and swollen hydrogels. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 5994–5999, 2006     

The adsorption behavior of cesium on poly(N-isopropylacrylamide/itaconic acid) copolymeric hydrogels

In this study, N-isopropylacrylamide/itaconic acid (NIPAAm/IA) hydrogels prepared by irradiating with γ radiation were used in experiments on cesium ion adsorption. The cesium ion adsorption capacity of the hydrogels was investigated as a function of Cs⁺ concentration, pH and temperature. The adsorption behavior of cesium was evaluated by using the radiotracer method. The adsorption isotherm models were applied to the experimental data, and it was seen that Freundlich isotherm explained the adsorption better than Langmuir isotherm. Two simplified kinetic models including pseudo-first-order and pseudo-second-order equation were selected to follow the adsorption processes. The Cs⁺ adsorption could be best described by the pseudo-first-order equation. The thermodynamic parameters including ΔG°, ΔH° and ΔS° for adsorption processes of Cs⁺ on the hydrogel were also calculated, and the negative ΔH° and ΔG° confirmed that the adsorption process was exothermic and spontaneous.     

Investigation of thermal behavior of poly(2‐hydroxyethyl methacrylate‐co‐itaconic acid) networks

The thermal behavior of poly(2‐hydroxyethyl methacrylate) [PHEMA] homopolymer and poly(2‐hydroxyethyl methacrylate‐co‐itaconic acid) [P(HEMA/IA)] copolymeric networks synthesized using a radiation‐induced polymerization technique was investigated by differential scanning calorimetry, thermogravimetric analysis, and Fourier transform infrared spectroscopy. The glass‐transition temperature (T_g) of the PHEMA homopolymer was found to be 87°C. On the other hand, the T_g of the P(HEMA/IA) networks increased from 88°C to 117°C with an increasing amount of IA in the network system. The thermal degradation reaction mechanism of the P(HEMA/IA) networks was determined to be different from the PHEMA homopolymer, as confirmed by thermogravimetric analysis. It was observed that the initial thermal degradation temperature of these copolymeric networks increased from 271°C to 300°C with IA content. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 1602–1607, 2007     

Self-aggregates of poly(aspartic acid) grafted with long alkyl chains

Summary Biodegradable poly(aspartic acid) (PASP) containing octadecyl chain grafts has been synthesized by thermal polycondensation of aspartic acid, aminolysis by octadecylamine, and followed by hydrolysis of remaining succinimide in polymer backbone. The sonicated suspension formed self-aggregates in aqueous solution. Size exclusion chromatography and dynamic light scattering indicated that self-aggregates became compact and particle size was reduced as increasing the amount of substituted octadecyl chains. In the case of low degree of substitution, self-aggregates assembled loosely due to low hydrophobic interaction. In the concentration range of 0.05–1.0%, the stability of aggregates was maintained due to effective hydrophobic interaction and electrostatic repulsion. Below pH 3.2, macroscopic phase-separation appeared in aqueous solution due to attraction of protonated PASP backbone. Received: 3 April 2000/Revised version: 6 July 2000/Accepted: 7 July 2000     

Synthesis and characterization of poly(2-hydroxyethyl methacrylate/itaconic acid) copolymeric hydrogels

In the present study poly(2-hydroxyethyl methacrylate-co-itaconic acid) (P(HEMA/IA)) hydrogels were synthesized by free-radical copolymerization of 2-hydroxyethyl methacrylate and itaconic acid in order to evaluate as controlled release drug delivery system. All polymerizations were performed in a mixture of water/ethanol with ethylene glycol dimethacrylate, as crosslinking agent, potassium persulfate, as initiator, and N, N, N′, N′-tetramethylethylene diamine, as activator. The samples were characterized by FTIR and SEM. Swelling kinetics and antibiotic release studies were performed using gravimetry and UV spectrophotometry, respectively. The antibacterial activity studies were performed bearing in mind that infections are the most common cause of biomaterial implant failure and represent a constant menace to the application of medical implants. The hemocompatibility testing was performed as imperative for medical devices intended for direct or indirect blood exposure. In accordance with the results of antibacterial assessment on gels loaded with antibiotics and hemolytic activity testing these gels exerted good bacterial growth inhibition and favorable hemolytic activity. The release profiles of antibiotics, evaluated in vitro conditions, were correspondent for antibacterial therapeutics. Therefore, it was concluded that (P(HEMA/IA)) gels could be propound for the potential application as drug delivery systems for the controlled release of antibiotics.