Rigid Poly Research Articles

Super-tough poly(butylene terephthalate) based blends by modification with core-shell structured polyacrylic nanoparticles

Abstract Core-shell structured polyacrylic nanoparticles (named CSPN) impact modifiers consisting of a rubbery poly(n-butyl acrylate) core and a rigid poly(methyl methacrylate) shell with a size of about 352 nm were synthesized by seed emulsion polymerization. The CSPN modifier with core-shell weight ratio 80/20 was used to toughen poly(butylene terephthalate) (PBT) by melt blending. With an increase in CSPN content, the impact strength and the elongation at break of PBT/CSPN blends increased significantly compared with those of PBT; however, the tensile strength decreased. It was found that the polymerization had a very high instantaneous conversion (> 93%) and overall conversion (99%). The core-shell structure of CSPN was examined by means of transmission electron microscope. Scanning electron microscope was used to observe the morphology of CSPN particle and fractured surfaces of the blends. The dynamic mechanical analyses of PBT/CSPN blends showed two merged transition peaks of PBT matrix, with the presence of CSPN modifier, which was responsible for the improvement of PBT toughness. The results indicated that the notched impact strength of PBT/CSPN blend with a weight ratio of 80/20 was 8.61 times greater than that of pure PBT where the brittle-ductile transition point appeared.

Processability, Thermal and Mechanical Properties of Rigid PVC/Kaolin Coated with Liquid Macromolecular Modifier Composites

Abstract In order to investigate the effect of kaolin coated with liquid macromolecular modifier (LKL) particles on the processability, thermal and mechanical properties of PVC materials, rigid poly(vinyl chloride) (PVC)/kaolin and PVC/kaolin coated with liquid macromolecular modifier (PVC/LKL) composites were both fabricated by melt mixing. The processability, dynamic mechanical behavior, mechanical properties and micro-structure of PVC/kaolin and PVC/LKL composites were studied by using torque rheometer, dynamic mechanical analysis (DMA), universal mechanical testing machine and scanning electron microscope (SEM). The results showed that the LKL particles improved the processability of PVC materials, while restrained the degradation of PVC materials during melt mixing due to the plasticization, toughening effect and compatibilization of the liquid macromolecular modifier (LMM). Moreover, the LMM could promote LKL particles uniformly dispersed in PVC matrix, and enhance the interface adhesion between LKL particles and PVC matrix. The notched impact strength and Tg of the PVC/LKL composites achieved 4.0 kJ/m2 and 95.2 °C, which enhanced 29% and 6 °C with respect to neat PVC materials, respectively.

Enhanced toughness of multilayer graphene‐filled poly(VInyl chloride) composites prepared using melt‐mixing method

In order to improve toughness of rigid poly(vinyl chloride) (PVC), we prepared multilayer graphene (MLG) filled PVC composites through conventional melt‐mixing methods by taking advantages of easy dispersion and high flexibility of graphene. Microstructure, static, and dynamic mechanical properties of the MLG/PVC composites were investigated in details. We found that a small amount of MLG loadings (0.36 wt%) could greatly increase tensile fracture toughness and impact strength of the MLG/PVC composites, which is mainly attributed to high flexibility of the crumpled MLG throughout PVC matrix. Moreover, the presence of MLG can weaken intermolecular interactions and improve segmental motion of PVC chains, consequently resulting in low glass transition temperature and high toughness of the MLG/PVC composites. By virtue of its enhanced toughness and easy operation, the MLG/PVC composites show great potential to be used as high‐performance composites in many fields. POLYM. COMPOS., 38:138–146, 2017. © 2015 Society of Plastics Engineers

Thermally Stable Antimicrobial PVC/Maleimido Phenyl Thiourea Composites

ABSTRACTFour novel antimicrobial maleimido phenyl thiourea derivatives were synthesized from N‐[4‐(chlorocarbonyl) phenyl] maleimide with phenyl thiourea and its derivatives (p‐methyl, o‐chloro, and p‐carboxy). Their structures were characterized by FTIR, 1H NMR, mass spectra, and elemental analyses. Their antimicrobial activities against three types of bacteria (Bacillus subtilis, Streptococcus pneumoniae, and Escherichia coli) and against three crop‐threatening pathogenic fungi (Aspergillus fumigatus, Geotricum candidum, and Syncephalastrum racemosum) were investigated. The results revealed that these derivatives are effective in inhibiting the growth of the tested bacteria and fungi as indicated from the inhibition zone diameter and minimum inhibitory concentration. The antibacterial activities of these derivatives were more effective against Gram‐positive bacteria than Gram‐negative bacteria. These derivatives were investigated as thermal stabilizers for rigid poly(vinyl chloride) at 180°C in air by measuring the rate of dehydrochlorination and the extent of discoloration. The results reveal the greater stabilizing efficiency of the investigated derivatives as shown by their longer thermal stability periods (Ts) and lower dehydrochlorination rates in relation to dibasic lead carbonate, cadmium–barium–zinc stearate, and n‐octyltin mercaptide industrial stabilizers. The stabilizing efficiency increases with the introduction of electron‐donating substituent groups in the aromatic ring of the stabilizer molecules. Moreover, the investigated stabilizers impart better color stability for the degraded samples as compared with the reference stabilizers.

Super-tough Poly(butylene terephthalate) Materials: Blending with CSSP Nanoparticles

Core-shell structured polyacrylic (CSSP) impact modifiers, consisting of a rubbery poly(n-butyl acrylate) core and a rigid poly(methyl methacrylate) shell, were synthesized by seed emulsion polymerization. The CSSP modifier with core-shell weight ratio 75/25 was used to modify the toughness of poly(butylene terephthalate) (PBT) by melt blending. The CSSP morphology was confirmed by TEM and SEM. Dynamic mechanical analyses of PBT/CSSP blends showed two merged transition peaks of PBT matrix. Increasing CSSP content increased elongation at break and impact strength, but decreased tensile strength. The notch impact strength of PBT/CSSP blends with weight ratio 85/15 was eight times greater than pure PBT.

Insights into the use of zinc–mannitol alkoxide as a novel thermal stabilizer for rigid poly(vinyl chloride)

ABSTRACTZinc–mannitol alkoxide (Zn–Man) was synthesized through alcohol exchange reaction, and investigated by means of Fourier transform infrared spectroscopy and elemental analysis. The thermal stability of Zn–Man for rigid poly(vinyl chloride) (PVC) was evaluated by Congo red testing, conductivity measurements, thermal aging testing, thermogravimetric analysis (TGA), and ultraviolet–visible (UV–vis) spectroscopy test. The experimental results demonstrate that the addition of Zn–Man not only apparently prolonged the static thermal stability time to approximately 96.5 min but also evidently improved the initial color of PVC. More importantly, the color of the PVC sheets stabilized with Zn–Man did not change to black within 180 min; this showed that no zinc‐burning phenomenon occurred. In addition, the results of TGA reveal that Zn–Man raised the initial degradation temperature of PVC to about 273.4°C. UV–vis testing indicated that the presence of Zn–Man decreased the content and shortened the length of the conjugated double bonds of PVC. The possible thermal stability mechanism is discussed. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42038.

Microfluidic Synthesis of Rigid Nanovesicles for Hydrophilic Reagents Delivery

AbstractWe present a hollow‐structured rigid nanovesicle (RNV) fabricated by a multi‐stage microfluidic chip in one step, to effectively entrap various hydrophilic reagents inside, without complicated synthesis, extensive use of emulsifiers and stabilizers, and laborious purification procedures. The RNV contains a hollow water core, a rigid poly (lactic‐co‐glycolic acid) (PLGA) shell, and an outermost lipid layer. The formation mechanism of the RNV is investigated by dissipative particle dynamics (DPD) simulations. The entrapment efficiency of hydrophilic reagents such as calcein, rhodamine B and siRNA inside the hollow water core of RNV is ≈90 %. In comparison with the combination of free Dox and siRNA, RNV that co‐encapsulate siRNA and doxorubicin (Dox) reveals a significantly enhanced anti‐tumor effect for a multi‐drug resistant tumor model.

Preparation and characterization of a core‐shell impact modifier based on (Acrylates and styrene)‐grafted ground tire rubber and its poly(vinyl chloride) composites

New impact modifiers composed of a ground tire rubber core and acrylates and styrene copolymer shell have been obtained by using a suspension grafting polymerization. The corresponding rigid poly(vinyl chloride)/grafted ground tire rubber (RPVC/GGTR) composites with different contents of GGTR were then prepared in a Haake torque rheometer. Similar composites with raw ground tire rubber (without grafting polymerization) have also been prepared for comparison. Thermal stability, processability, mechanical properties, and surface morphology of the composites were extensively investigated by thermal gravimetric analysis (TGA), rheological measurement, tensile and impact tests, and scanning electron microscopy (SEM). The results showed that GGTR improved the processability of the RPVC/GGTR composites. The Izod impact strength of the composites could be significantly enhanced by the GGTR, while the tensile strength of the composites was almost unchanged, thus showing a large potential application in the fields of building materials such as poly(vinyl chloride) profiles. J. VINYL ADDIT. TECHNOL., 22:452–459, 2016. © 2015 Society of Plastics Engineers

Synthesis of New Thiophene Derivatives and Their Use as Photostabilizers for Rigid Poly(vinyl chloride)

Five new thiophenes, namely,N-[(3-bromo-2-methylthiophen-5-yl)methylene]-4-methoxyaniline (4a),N-[(3-bromo-2-methylthiophen-5-yl)methylene]-3,4-dimethoxyaniline (4b),N-[(3-bromo-2-methylthiophen-5-yl)methylene]-3,4-dimethylaniline (4c), 3-[(3-bromo-2-methylthiophen-5-yl)methyleneamino]-2-methylquinazolin-4(3H)-one (4d), and 3-[(3-bromo-2-methylthiophen-5-yl)methyleneamino]-2-isopropylquinazolin-4(3H)-one (4e), have been synthesized. All of these materials brought about a reduction in the level of photodegradation of poly(vinyl chloride) (PVC) films containing the synthesized thiophenes (0.5%; by weight). The results obtained showed that the extent of photostabilization of PVC in the presence of an additive was in the order4e > 4d > 4b > 4a > 4c. For the most favorable additive (4e), the rate of appearance of infrared absorption bands of degradation products was reduced by around two-thirds, while the quantum yield of chain scission was calculated to be reduced by a factor of more than one thousand. It is suggested that the additives may help stabilize PVC by direct absorption of UV radiation and dissipation of the energy as heat or that electrostatic attraction between the additives and PVC may assist transfer of energy from excited state PVC to the additive, from where it can be dissipated.

Ultra-violet spectra studies of photodegradation of PVC films in presence of Fe(III) chelate complex

A complex of Fe(III) with 4-amino-5-(pyridyl)-4 H -1,2,4-triazole-3-thiol was prepared and evaluated as a photodegradation for rigid poly(vinyl chloride) (PVC). Polyvinyl chloride dissolved with Fe(III) complex in THF solvent to form PVC films of 5% (40 μm) thickness containing different concentrations (0.01, 0.02, 0.03, 0.04 and 0.05 g) of the complex by weight. These different samples were produced by the casting method from the solvent. The photodegradation of films was investigated using UV-visible spectra. The photostabilization activity of these compounds was determined by calculating the photodecomposition rate constant ( K d ) for modified PVC films against a blank.

Preparation of core-shell structured polyacrylic modifiers and effects of the core-shell weight ratio on toughening of poly(butylene terephthalate)

Core-shell structured polyacrylic (named CSSP) impact modifiers consisting of a rubbery poly(n-butyl acrylate) core and a rigid poly(methyl methacrylate) shell with a size of about 353 nm were prepared by seed emulsion polymerization. The CSSP modifiers with different core-shell weight ratios (90/10, 85/15, 80/20, 75/25, 70/30, 65/35 and 60/40) were used to modify the toughness of poly(butylene terephthalate) (PBT) by melt blending. It was found that the polymerization had a very high instantaneous conversion (> 95.7%) and overall conversion (99.7%). The morphology of the core-shell structure was confirmed by means of transmission electron microscopy. Scanning electron microscopy was used to observe the morphology of the fractured surfaces. Differential scanning calorimeter was used to study the crystallization behaviors of PBT/CSSP blends. The dynamic mechanical analyses of PBT/CSSP blends showed two merged transition peaks of PBT matrix, with the presence of CSSP core-shell structured modifier, that were responsible for the improvement of PBT toughness. The results indicated that the notch impact strength of PBT/CSSP blends with a core-shell weight ratio of 75/25 was almost 8.64 times greater than that of pure PBT, and the mechanical properties agreed well with the SEM observation.

Photochemical reaction in azobenzene-containing rigid poly(amide acid) networks

Photochemical reaction of azobenzenes embedded into rigid poly(amide acid) (PAA) networks, which undergo reversible photomechanical response upon alternating irradiation of 405 nm and 532 nm lights, was explored. Azobenzene functionalities are incorporated into the PAA backbone that is end-linked with tri- and tetra-armed crosslinkers, 1,3,5-tris(4-aminophenyl)benzene (TAPB) and tetra(4-aminophenyl)methane (TAPM), respectively, to give photoresponsive polymer networks. It was discovered that the trans-to-cis photoisomerization rate of azobenzene moiety is highly dependent on the network architecture. Before crosslinking, the photoisomerization rate is considerably low and totally independent on molecular weights of the backbone whereas, after crosslinking, the rate is dramatically enhanced and highly dependent on the molecular weights. A crosslinker effect on the photomechanical response is also disclosed. These results are attributed to an inter-chain aggregation of PAA backbones. The bulky structure and superior connectivity of TAPM make the network structure spatially extended with less defects, which not only prevents the aggregation but also contributes to the nano-to-macroscopic propagation of molecular deformation of azobenzene.

Thermally stable antimicrobial PVC/maleimido phenyl urea composites

Four novel antimicro bial maleimido phenyl urea derivatives were synthesized from N-[4-(chlorocarbonyl) phenyl] maleimide with phenyl urea derivatives (p-methyl, o-chloro and p-carboxy). They were characterized by FTIR, 1H-NMR, mass spectra, elemental analyses and antimicrobial activities. These derivatives were investigated as thermal stabilizers for rigid poly(vinyl chloride) at 180 °C in air by measuring the rate of dehydrochlorination and the extent of discoloration. The results reveal the greater stabilizing efficiency of the investigated derivatives as shown by their longer thermal stability periods (Ts) and lower dehydrochlorination rates in relation to dibasic lead carbonate, cadmium-barium-zinc stearate and n-octyltin mercaptide industrial stabilizers. The stabilizing efficiency increases with the introduction of electron donating substituent groups in the aromatic ring of the stabilizer molecules. Moreover, the investigated stabilizers impart better color stability for the degraded samples as compared with the reference stabilizers.

Thermally stable antimicrobial polyvinylchloride/maleimido aromatic hydrazide composites

Antimicrobial novel substituted maleimido aromatic hydrazides were synthesized from N‐[4‐(chlorocarbonyl) phenyl] maleimide with salicylhydrazide, p‐aminobenzohydrazide, or p‐aminosalicylhydrazide. They were characterized by Fourier transform infrared (FTIR), hydrogen‐1 nuclear magnetic resonance (1H‐NMR), mass spectra, elemental analyses, and antimicrobial activities. These derivatives were investigated as thermal stabilizers for rigid poly(vinyl chloride) (PVC) at 180°C in air by measuring the rate of dehydrochlorination, the extent of discoloration, and the changes that occurred in the molecular masses of the degraded PVC samples. The previously reported stabilizing efficiency data of a nonsubstituted derivative, which was synthesized from N‐[4‐(chlorocarbonyl) phenyl] maleimide with benzohydrazide, is also given for comparison. The results reveal the greater stabilizing efficiency of the investigated derivatives as shown by their longer thermal stability (Ts) periods and lower dehydrochlorination rates in relation to dibasic lead carbonate, cadmium‐barium‐zinc stearate, and n‐octyltin mercaptide industrial stabilizers. The stabilizing efficiency increases with the introduction of electron donating substituent groups in the aromatic ring of the stabilizer molecules. Moreover, the investigated stabilizers impart better color stability for the degraded samples as compared with the reference stabilizers. A synergistic effect is achieved when the materials under investigation were mixed in various weight ratios with any of the reference stabilizers, reaching its maximum at equivalent weight ratio of the investigated stabilizer to the reference one. J. VINYL ADDIT. TECHNOL., 22:247–258, 2016. © 2014 Society of Plastics Engineers

Multicore iron oxide mesocrystals stabilized by a poly(phenylenepyridyl) dendron and dendrimer: role of the dendron/dendrimer self-assembly.

We report the formation of multicore iron oxide mesocrystals using the thermal decomposition of iron acetyl acetonate in the presence of the multifunctional and rigid poly(phenylenepyridyl) dendron and dendrimer. We thoroughly analyze the influence of capping molecules of two different architectures and demonstrate for the first time that dendron/dendrimer self-assembly leads to multicore morphologies. Single-crystalline ordering in multicore NPs leads to cooperative magnetic behavior: mesocrystals exhibit ambient blocking temperatures, allowing subtle control over magnetic properties using a minor temperature change.

Application of response surface methodology in describing fusion characteristics of rigid poly(vinyl chloride)/nanoclay/wood flour/calcium carbonate hybrid nanocomposites

The fusion characteristics of poly(vinyl chloride) hybrid nanocomposites containing different amounts of nanocalcium carbonate, wood flour, and nanoclay fillers were investigated utilizing response surface methodology (RSM). Various nanocomposites were prepared through a two‐step mixing process, wherein the minimum and maximum torque values, the fusion time, and fusion factor were monitored through torque‐time plastograms provided during melt processing. A quadratic model was developed by using RSM to probe the individual and interactive effects of nanoclay, nanocalcium carbonate, and wood flour on the fusion parameters. Optimized formulations with enhanced fusion properties were achieved by using contour plots of RSM. J. VINYL ADDIT. TECHNOL. 21:183–190, 2015. © 2014 Society of Plastics Engineers

Toughening of poly(butylene terephthalate) by polyacrylic impact modifier

Core–shell structured polyacrylic (named ACR) impact modifiers consisting of a rubbery poly(n-butyl acrylate) (BA) core and a rigid poly(methyl methacrylate) shell with a size of about 310 nm were prepared by seed emulsion polymerization. The ACR modifiers with different core–shell weight ratios (85:15; 80:20; 75:25; 70:30) were used to modify the toughness of poly(butylene terephthalate) (PBT) by melt blending. It was found that the polymerization had a very high instantaneous conversion (>90 %) and overall conversion (98 %). The ACR latexes had an obvious core–shell structure confirmed by transmission electron microscope. The mechanical properties of the PBT/ACR blends were evaluated, and scanning electron microscope (SEM) was used to observe the fractured morphology. Dynamic mechanical analysis and differential scanning calorimeter were used to study the molecular movement and crystallization behaviors of PBT/ACR blends. The results indicated that with an appropriate value of the core–shell weight ratio, poly(BA) could disperse well in the matrix and the brittle–ductile transition point could emerge. As a result, the notch impact strength of PBT/ACR blends with a core–shell weight ratio of 80:20 was 6.7 times greater than that of pure PBT, and the mechanical properties agreed well with the SEM observation.

Detailed study on fusion characteristics of rigid poly(vinyl chloride) nanocomposites: The comparison of using multiple regression analysis and artificial neural network

Fusion behavior of poly(vinyl chloride) (PVC) compounds plays an important role in the development of physical properties of processed material. The fusion characteristics in PVC processing are governed by material variables that affect the fusion with some interactions. In this research, the aim was to characterize the effects of formulation ingredients on fusion characteristics of PVC. Four material parameters, including the contents of nanoclay (NC), azodicarbonamide, calcium stearate, and processing aid, are proposed as affecting variables. The fusion time (FT) as well as fusion factor (FF) are considered fusion indicators and are experimentally determined in some different levels of affecting parameters. The multivariable regression analysis (MRA) and the Artificial Neural Network (ANN) modeling are considered as two analytical methods. The regression analysis result for the FT denotes, in part, significant linear and quadratic effects of NC and also its significant interactions with azodicarbonamide and calcium stearate, whereas that of FF indicates only a linear effect of NC. ANN modeling is performed with a three‐layer (input, hidden, and output) neural network. The results of the comparison of the MRA and ANN predictions with experimental values are reported as the correlation coefficient (R2), mean‐square error, and mean absolute percentage error for both FF and FT parameters. The obtained values clearly denote that the ANN results are more precise and especially more general than those of MRA. However, in the case of FT, improvement of the ANN modeling is much greater than that of FF. J. VINYL ADDIT. TECHNOL., 21:147–155, 2015. © 2014 Society of Plastics Engineers

Macromol. Chem. Phys. 10/2014

Front Cover: The framework structure of rigid poly(amide acid) and polyimide networks can be tuned by the selection of a robust and symmetric crosslinker structure. The S4-symmetric four-armed crosslinker can provide homogeneous network structures compared with the C3-symmetric three-armed crosslinker. Further details can be found in the article by N. Yoshihara, N. Hosono,* R. Ohshima, K. Totani, and T. Watanabe* on page 988.

Processability, morphology, thermal, and mechanical properties of rigid PVC composites with liquid macromolecular modifier-coated CaCO3

Rigid poly(vinyl chloride) (PVC)/CaCO3 and PVC/liquid macromolecular modifier (LMM) coated CaCO3 (PVC/LCC) composites were both fabricated by melt mixing. The processability, micro-structure, dynamic mechanical behavior and mechanical properties of PVC/CaCO3 and PVC/LCC composites were studied by using torque rheometer, scanning electron microscope (SEM), dynamic mechanical analysis (DMA), and universal mechanical testing machine. The results showed that the synergistic effect of LMM and CaCO3 particles accelerated the plasticization of PVC resins. The processability of PVC/LCC composites was improved. The dispersion of LCC in PVC matrix was improved by the modification of CaCO3 particles with LMM. The Tgs of PVC/LCC composites were enhanced by filling with LCC. Because of the synergistic toughening of LMM and CaCO3 particles, the PVC/LCC composites exhibited excellent notched impact properties at the optimum value of LCC particles content. POLYM. COMPOS., 36:1286–1292, 2015. © 2014 Society of Plastics Engineers