Effect of plasticizer and curing system on freezing resistance of rubbers

At glass transition temperature, T_g the rubber compound becomes stiff and brittle and it loses all its rubbery characteristics. This article deals with the changes in T_g of rubber blends based on natural rubber and polybutadiene rubber of varying vinyl content having different types and content of plasticizers, different curing systems and its effect on physico‐mechanical properties to improve its freezing resistance. The plasticizers used were dioctylphthalate (DOP), tricrecylphosphate (TCP), dioctyladipate (DOA), and oil type plasticizers like parafinic oil (P#2) and aromatic oil (A#2). Among the plasticizers, when DOP and DOA content was high, an appreciable decrease of T_g was found compared to TCP. Moreover, there was a remarkable decrease of T_g using DOA plasticizer, which shows more effective on freezing resistance. However, there was not much change in T_g with oil‐type plasticizers with high oil content compared to TCP plasticizer. The effect of cross‐linking systems such as conventional sulfur vulcanization (CV), efficient sulfur vulcanization (EV), and dicumyl peroxide (DCP) and rubber blends with varying vinyl content in polybutadiene rubber were also carried out. It was found that T_g in different cross‐linking system decreased in this order: CV < EV < DCP. It reveals that DCP cross‐linking system affect more for improving freezing resistance. Physico‐mechanical properties such as tensile strength, tear strength, hardness were also measured. The ratio of initial slope (M₀) to steady‐state slope (M₁), M₀/M₁ in tensile curves of different blends were verified, which in turn related to the physico‐mechanical properties and freezing resistance of rubber compounds. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 39795.     

A new class of transparent polymeric materials. II. Synthesis and properties of poly(N-cyclohexylmaleimide-alt-isobutene) modified with lauryl methacrylate

Transparent polymeric materials with high heat resistance and low water absorption were designed based on the alternating copolymers of N-substituted maleimide (RMI) with isobutene (IB). The N-substituent of the maleimide significantly affected the glass transition temperature (T_g) and water absorption of the copolymers. Poly(N-cyclohexylmaleimide-alt-JB) [poly(CHMI-IB)] showed a T_g value as high as 192°C and relatively low water absorption. Furthermore, the incorporation of a small amount of lauryl methacrylate in the copolymers was confirmed to reduce the water absorption of the copolymer drastically, although it decreased the T_g of the copolymers at the same time. Poly(CHMI-IB), containing 4 mol % lauryl methacrylate, showed a good balance of excellent transparency, high heat resistance, acceptable mechanical properties, and low water absorption. The heat deflection temperature was as high as 141°C. The water absorption at 23°C after immersion for 14 days was 0.56% and the dimensional change after 7 days was 0.06%. They are half and one-quarter of those of poly(methyl methacrylate), respectively. © 1996 John Wiley & Sons, Inc.     

Rigid thermosetting liquid molding resins from renewable resources. II. Copolymers of soybean oil monoglyceride maleates with neopentyl glycol and bisphenol A maleates

Soybean oil monoglycerides (SOMG), obtained by the glycerolysis of soybean oil, were reacted with maleic anhydride to produce SOMG maleate half esters. The copolymers of the SOMG maleates with styrene produced rigid thermosetting polymers. The dynamic mechanical analysis (DMA) of this polymer showed a glass‐transition temperature (T_g) around 133°C and a storage modulus (E′) value around 0.94 GPa at 35°C. The tensile tests performed on this polymer showed a tensile strength of 29.36 MPa and a tensile modulus of 0.84 GPa. Mixtures of SOMG with neopentyl glycol (NPG) and SOMG with bisphenol A (BPA) were also maleinized under the same reaction conditions and the resulting maleates were then copolymerized with styrene. The resulting polymers were analyzed for their mechanical properties. The T_g of the copolymers of the SOMG/NPG maleates with styrene was 145°C and the E′ value at 35°C was 2 GPa. The tensile strength of this polymer as calculated from the stress–strain data was 15.65 MPa and the tensile modulus was 1.49 GPa. The T_g of the copolymers of SOMG/BPA maleates, on the other hand, was found to be around 131°C and the E′ value was 1.34 GPa at 35°C. The changes observed in the mechanical properties of the resulting polymers with the introduction of NPG maleates and BPA maleates to the SOMG maleates can be explained by the structural changes on the polymer backbone. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 972–980, 2002     

Sustainable synthesis of bio‐based hyperbranched ester and its application for preparing soft polyvinyl chloride materials

In this study, bio‐based hyperbranched ester was synthesized from castor oil. The chemical structure of the bio‐based hyperbranched ester obtained was characterized with Fourier transform infrared and ¹H NMR spectra. Soft polyvinyl chloride (PVC) materials were prepared via thermoplastic blending at 160 °C using bio‐based hyperbranched ester as plasticizer. The performances including the thermal stability, glass transition temperature (T_g), crystallinity, tensile properties, solvent extraction resistance and volatility resistance of soft PVC materials incorporating bio‐based hyperbranched ester were investigated and compared with the traditional plasticizer dioctyl phthalate (DOP). The results showed that bio‐based hyperbranched ester enhanced the thermal stability of the PVC materials. The T_g of PVC incorporating bio‐based hyperbranched ester was 23 °C, lower than that of PVC/DOP materials at 28 °C. Bio‐based hyperbranched ester showed a better plasticizing effect, solvent extraction resistance and volatility resistance than DOP. The plasticizing mechanism is also discussed. © 2018 Society of Chemical Industry     

Properties of poly(vinyl chloride) fibers crosslinked by 2-dibutylamino-4,6-dimercapto-1,3,5-triazine

PVC fibers, fastened to a needle frame, were crosslinked by 2-dibutylamino-4, 6-dimercapto-1,3,5-trizine in the presence of tetra-n-butylammonium bromide and alkali in water at 96°C. Solvent resistance, characterized by the gel fraction of THF, improves markedly. Mechanical properties of the fibers investigated by tensile tests at 20°C show that both the modulus and tensile strength at break increase, while elongation at break decreases over 40% gel content. Creep tests indicate that the resistance to heat deformation improves by crosslinking. The heat distortion temperature increases by 12°C at 75% gel content. Results of dynamic tests show that the T_g of PVC fibers determined by a peak in the loss modulus (E'') increases from 40% gel content. Dynamic modulus (E') increases by 74% at 23°C and the T_g by 37°C in the case of crosslinked PVC fibers having a 92% gel content. The shrinkage of PVC fibers in hot water at 94°C for 30 min decreases more than 50% over 75–80% gel content indicating the improved resistance to heat deformation.     

Improvement in the heat resistance of poly(vinyl chloride) profile with styrenic polymers

The styrenic polymers poly(α‐methylstyrene‐acrylonitrile) (α‐MSAN) and poly(acrylonitrile‐butadiene‐styrene) (ABS) and (three types) were used to improve the heat resistance of poly(vinyl chloride) (PVC). The glass transition temperature (T_g) and miscibility were analyzed by dynamic mechanical thermal analysis (DMTA). Effects of composition on heat distortion temperature (HDT) were investigated with the different styrenic polymers. Other physical properties such as mechanical properties and melt flow rate (MFR) were also determined. Morphology was observed by scanning electron microscopy (SEM) in order to support the mechanical property results. The PVC was miscible with α‐MSAN but partially miscible with the ABS series, and α‐MSAN was much more effective in enhancing the T_g and HDT of rigid PVC than the ABS series as for mechanical properties, the addition of α‐MSAN could improve the tensile strength, bending strength, and bending modulus but decrease the impact strength of the materials compared with the addition of the ABS series. Improvement in processability was observed in the MFR results with the addition of the styrenic polymers. On the basis of all the properties, the formulation with an α‐MSAN content of 30 phr (parts per hundred parts of resin) was superior for heat‐resistant PVC profile. The HDT of PVC could be increased from 76.9°C to 85.4°C (measured under the maximum bending stress of 0.45 MPa) and combined with good mechanical properties and processability by the addition of 30 phr of α‐MSAN. Also, a heat‐resistant PVC profile was successfully fabricated. J. VINYL ADDIT. TECHNOL., 2011. © 2011 Society of Plastics Engineers     

Flexible all‐aromatic polyesterimide films with high glass transition temperatures

A series all‐aromatic poly(esterimide)s with different molar ratios of N‐(3′‐hydroxyphenyl)‐trimellitimide (IM) and 4‐hydroxybenzoic acid (HBA) (IM/HBA = 0.3/0.7 and 0.7/0.3) was prepared with the aim to design flexible high T_g films. Melt‐pressed films, either from high molecular weight polymer or cured phenylethynyl precursor oligomers, exhibit T_gs in the range of 200 °C to 242 °C and are brittle. After a thermal stretching procedure, the films became remarkably flexible and very easy to handle. In addition, the thermally stretched 3‐IM/7‐HBA and 7‐IM/3‐HBA films show tensile strengths of 108 MPa and 169 MPa, respectively. Thermal treatment increased the T_g of 3‐IM/7‐HBA from 205 °C to 248 °C, whereas the T_g of 7‐IM/3‐HBA increased from 230 °C to 260 °C. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 133, 44774.     

Design and properties of a series of high‐temperature thermoplastic elastomeric blends from polyamides and functionalized rubbers

A series of high‐temperature thermoplastic elastomers (TPEs) and thermoplastic vulcanisates (TPVs) were successfully developed based on two different types of heat resistant polyamide (PA) (25 parts by weight)—PA‐12 and PA‐6, in combination with three different functionalized rubbers (75 parts by weight) of varying polarity, e.g., maleic anhydride grafted ethylene propylene diene terpolymer (MA‐g‐EPDM), sulphonated ethylene propylene diene terpolymer, and carboxylated acrylonitrile butadiene rubber, by melt mixing method. These rubbers have low level of unsaturation in its backbone, and the plastics showed high melting range. Thus, the developed TPEs and TPVs were expected to be high temperature resistant. Resol type resin was used for dynamic vulcanization to further increase the high temperature properties of these blends. Interestingly, initial degradation temperature of the prepared blends was much higher (421 °C for MA‐g‐EPDM/PA‐12) than the other reported conventional TPEs and TPVs. Fourier transform infrared analysis described the interactive nature of the TPEs and TPVs, which is responsible for their superior properties. The maximum tensile strength with lowest tension set was observed for the carboxylated acrylonitrile butadiene rubber/PA‐12 TPV. Mild increase in mechanical properties without any degradation was observed after recycling. Dynamic mechanical analysis results showed two distinct glass transition temperatures and indicated the biphasic morphology of the blends, as evident from the scanning electron microscopy. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45353.     

Simultaneous interpenetrating polymer networks based on bromoacrylated castor oil polyurethane

In the first part of this study, simultaneous addition of bromine and acrylate to the double bonds of castor oil was achieved. In the second part of the study, bromoacrylated castor oil (BACO) was reacted with toluenediisocyanate (TDI), to form a prepolyurethane (BACOP). The prepolyurethanes were reacted with styrene (STY), 2‐hydroxyethyl methacrylate (HEMA), methyl methacrylate (MMA), and 3‐(acryloxy)‐2‐hydroxy propyl methacrylate (AHPMA) free radically, using the acrylate functional group to prepare the simultaneous interpenetrating polymer networks (SINs). 2,2′‐Azobis (isobutyronitrile) (AIBN) was used as the initiator and diethylene glycol dimethacrylate (DEGDMA) was used as the crosslinker. BACO and BACOP were characterized by IR, ¹H‐NMR, and ¹³C‐NMR techniques. Synthesized polymers were characterized by their resistance to chemical reagents, thermogravimetric analysis, and dynamic mechanical thermal analyzer (DMTA). All the polymers decomposed with 6–10% weight loss in a temperature range of 25–240°C. MMA‐type SIN showed the highest T_g (126°C), while STY‐type SINs showed the highest storage modulus (8.6 × 10⁹ Pa) at room temperature, with respect to other synthesized SINs. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 2947–2955, 2006     

Effect of crosslink structures on dynamic mechanical properties of natural rubber vulcanizates under different aging conditions

The effects of crosslink structures on the dynamic mechanical properties (DMPs) of unfilled and carbon black N330‐filled natural rubber (NR) vulcanizates cured with conventional (CV), semiefficient (SEV), and efficient (EV) cure systems and having about the same total crosslink densities were investigated before and after aerobic and anaerobic aging at 100°C. The three unfilled NR vulcanizates cured with the CV, SEV, and EV systems had about the same mechanical loss factor (tan δ) values at about 0°C but showed some apparent differences in the tan δ values in the order EV > SEV > CV at relatively high temperatures of 40–80°C before aging. However, N330‐filled NR vulcanizates gave higher tan δ values than the unfilled vulcanizates and showed little effect of the crosslink types on the tan δ at different temperatures over the glass‐transition temperature (T_g) before aging. Aerobic heat aging increased the T_g and tan δ values of the vulcanizates over a wide range of temperatures from ?80 to 90°C that was mainly due to the changes in the total density and types of crosslinks. The unfilled vulcanizates cured with the CV system showed the greatest change in DMP because of their poor resistance to heat aging. Aerobic heat aging of NR vulcanizates caused a more significant change in the DMP than anaerobic heat aging because of the dominant effect of the oxidative degradation during aerobic heat aging on the main‐chain structure, crosslink structures, and DMPs of the vulcanizates. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 710–718, 2001     

Studies on glass transition temperature of mono and bilayer protein films plasticized by glycerol and olive oil

Thermomechanical and thermal properties of whey protein, maize prolamin protein (zein), and the laminated whey protein–zein films were studied. The dynamic mechanical (thermal) analysis (DMTA) results showed that the single zein film had higher T_g than single whey protein and zein–whey laminated films. The shift in the T_g values of films from 31.2°C in whey protein film and 88.5°C in the zein film to 82.8°C in the laminated whey protein–zein films may be implied some interaction formation between the two polymers. The small tan δ peaks were observed at ?50°C in zein–glycerol films and at ?22.37°C in the whey protein films and can be related to β‐relaxation phenomena or presence of glycerol rich region in polymer matrix. Zein‐olive oil and zein–whey protein–olive oil films showed tan δ peaks corresponded the T_g values at 113.8, and 92.4°C, respectively. Thus, replacing of glycerol with olive oil in film composition increased T_g. A good correspondence was obtained when DSC results were compared with the tan δ peaks in DMTA measurements. DSC thermograms suggested that plasticizers and biopolymers remained a homogeneous material throughout the cooling and heating cycle. The results showed that T_g of zein–glycerol films predicted by Couchman and Karasz equation is very close to value obtained by DSC experiments. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Effects of reaction and cure temperatures on morphology and properties of poly(ester‐urethane)

Poly(ester‐urethane) was synthesized from poly(ethylene glycol adipate) (PEG) and 2,4‐toluene diisocyanate (TDI) to study the effects of reaction temperature and cure temperature on the crystallization behavior, morphology, and mechanical properties of the semicrystalline polyurethane (PU). PEG as soft segment was first reacted with TDI as hard segment at 90, 100, and 110°C, respectively, to obtain three kinds of PU prepolymers, coded as PEPU‐90, PEPU‐100, and PEPU‐110. Then the PU prepolymers were crosslinked by 1,1,1‐tris (hydroxylmethyl) propane (TMP) and were cured at 18, 25, 40, 60, and 80°C. Their structure and properties were characterized by attenuated total reflection Fourier transform infrared, wide‐angle X‐ray diffraction, scanning electron microscopy, dynamic mechanical analysis, and tensile testing. With an increase of the reaction temperature from 90 to 100°C, the crystallinity degree of soft segment decreased, but interaction between soft and hard segments enhanced, leading to the increase of the glass transition temperature (T_g) of soft domain and tensile strength. When the cure temperature was above 60°C, miscibility between soft and hard segments of the PEPU films was improved, resulting in relatively low crystallinity and elongation at break, but high soft segment T_g and tensile strength. On the whole, all of the PEPU‐90, PEPU‐100, and PEPU‐110 films cured above 60°C possessed higher tensile strength and elongation at break than that of the films cured at other temperatures. The results revealed that the reaction temperature and cure temperature play an important role in the improvement of the crosslinking structure and mechanical properties of the semicrystalline PU. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 708–714, 2006     

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     

Preparation of poly(styrene‐co‐isobornyl methacrylate) beads having controlled glass transition temperature by suspension polymerization

The styrene (St) and isobornyl methacrylate (IBMA) random copolymer beads with controlled glass transition temperature (T_g), in the range of 105–158°C, were successfully prepared by suspension polymerization. The influence of the ratios of IBMA in monomer feeds on the copolymerization yields, the molecular weights and molecular weight distributions of the produced copolymers, the copolymer compositions and the T_gs of these copolymers was investigated systematically. The monomer reactivity ratios were r₁ (St) = 0.57 and r₂ (IBMA) = 0.20 with benzyl peroxide as initiator at 90°C, respectively. As the mass fraction of IBMA in monomer feeds was about 40 wt %, it was observed that the monomer conversion could be up to 90 wt %. The fractions of IBMA unit in copolymers were in the range of 35–40 wt % and T_gs of the corresponding copolymers were in the range of 119.6–128°C while the monomer conversion increased from 0 to greater than 90 wt %. In addition, the effects of other factors, such as the dispersants, polymerization time and the initiator concentration on the copolymerization were also discussed. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Dynamic Mechanical Analysis of Amorphous-Phase Organization in Acrylic Polymers

Factors affecting polymer network organization were studied in highly crosslinked acrylics of the type used in dental adhesive resins. The variables tested were comonomer content and processing conditions. BisEMA (2,2,-bis[4-(2-methacryloyloxyethoxy)-phenyl]-propane) and BisEMA + TEGDMA (triethyleneglycol dimethacrylate) were cured with and without 25% comonomer. Comonomers had characteristics that are expected to influence intrachain organization in amorphous phases: TEGDMA, crosslinking; methyl methacrylate (MMA), monomer conversion; isobornyl methacrylate (IBM), low cure shrinkage; tetrahydrofurfuryl methacrylate (THFM), antiplasticization. Dynamic mechanical analysis temperature scans were run at 0.1 Hz 2h or 24h after ambient cure, or 24h postcure after heating at 75° or 125°C. After 24h, tan δ maxima occurred in ranges centering on approximately -30°, 75° and 150°C (T_g). Heating at 125°C nearly eliminated all peaks except T_g, reduced tan δ peaks and increased T_g by 0–14°. T_g increased in the order: TEGDMA>125°C>IBM>MMA>75°C>2h>24h>THFM. The ability to crosslink, and postcure heating at 125°C, were the more important factors found to increase intrachain organization in amine-promoted, unfilled BisEMA resins of the type used in dental sealants, luting cements and bulk-filling resin composite materials.     

Preparation and characterization of high‐temperature resistance polyimide foams

A new high‐temperature resistance polyimide foam was synthesized from 2,3,3′,4′‐biphenyltetracarboxylic dianhydride (α‐BPDA) and p‐phenylenediamine (p‐PDA). The structures and foaming process of polyimide precursor powders were characterized by wide‐angle X‐ray diffractometer (WXRD) and the self‐made visualization device, respectively. The imidization degree, thermal mechanical properties and thermal stability of the polyimide foams with different post‐treatment temperatures were also measured by fourier transform infrared spectrometer spectrum (FTIR), dynamic thermal mechanical anaylsis (DMTA), and thermogravimetric analysis (TGA). Results showed that the inflation onset temperatures of polyimide precursor powders ranged from 122 to 135°C with varying the heating rate. And the increase in the imidization degree, glass transition temperatures (T_g) and temperatures for 5 wt% mass loss of high‐temperature resistance polyimide foams can be achieved with increasing post‐treatment temperature. It was quite surprising to find that T_g of high‐temperature resistance polyimide foam post‐treated at 420°C was up to above 450°C, and the char yield at 800°C was more than 60%. POLYM. ENG. SCI., 2010. © 2010 Society of Plastics Engineers     

Thermal and mechanical properties of photocured organic–inorganic hybrid nanocomposites of terpene‐based acrylate resin and methacrylate‐substituted polysilsesquioxane

Diacrylate compounds derived from α‐pinene and limonene (TDAs: TDA‐1 and TDA‐2) were photocured with methacryl‐substituted polysilsesquioxane (ME‐PSQ) prepared from 3‐(trimethoxysilyl)propyl methacrylate and tetramethylammonium hydroxide (TMAOH) in the TDA/ME‐PSQ weight ratio of 20 : 0, 20 : 1, 20 : 2, 20 : 3, and 20 : 4. All the photocured TDA/ME‐PSQ hybrid nanocomposites became transparent. The thermomechanical analysis of the cured TDA/ME‐PSQ revealed that the glass transition temperature (T_g) increased, the thermal expansion coefficient above T_g decreased with increasing ME‐PSQ content, and that the TDA‐1/ME‐PSQ had ca. 30°C greater T_g than the TDA‐2/ME‐PSQ with the same ME‐PSQ content. Also, the dynamic mechanical analysis revealed that the TDA‐1/ME‐PSQ had much greater storage modulus at around 150°C than the corresponding TDA‐2/ME‐PSQ. The flexural strength and modulus of the TDA/ME‐PSQ nanocomposites at 20°C had maximum at ME‐PSQ content 4.8 and 13.0 wt %, respectively. As a whole, the thermal and mechanical properties of the nanocomposites were improved by the addition of ME‐PSQ, and those of TDA‐1/ME‐PSQ nanocomposites were superior to those of TDA‐2/ME‐PSQ. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Synthesis and characterization of soluble poly(arylene ether ketone)s with high glass transition temperature based on 3,6‐bi(4‐fluorobenzoyl)‐N‐alkylcarbazole

3,6‐bi(4‐fluorobenzoyl)‐N‐methylcarbazole and 3,6‐bi(4‐fluorobenzoyl)‐N‐ethylcarbazole were synthesized and used to prepare poly(arylene ether ketone)s (PAEKs) with high glass transition temperatures (T_g) and good solubility. High molecular weight amorphous PAEKs were prepared from these two difluoroketones with hydroquinone, phenolphthalein, 9,9‐bis(4‐hydroxyphenyl)fluorene and 4‐(4‐hydroxylphenyl)‐2,3‐phthalazin‐1‐one, respectively. All these polymers presented high thermal stability with glass transition temperatures being in the range 239–303 °C and a 5% thermal weight loss temperature above 460 °C. Compared with the T_g of phenolphthalein‐based PAEK (PEK‐C), fluorene‐based PAEK (BFEK) and phthalazinone‐based PAEK (DPEK) not containing a carbazole unit, these polymers presented a 30–50 °C increase in T_g. Meanwhile, PAEKs prepared from N‐ethylcarbazole difluoroketone showed good solubility in ordinary organic solvents, and all polymers exhibited excellent resistance to hydrochloric acid (36.5 wt%) and sodium hydroxide (50 wt%) solutions. In particular, phthalazinone‐based PAEK bearing N‐ethylcarbazole afforded simultaneously a T_g of 301 °C with good solubility. Tensile tests of films showed that these polymers have desirable mechanical properties. The carbazole‐based difluoroketones play an important role in preparing soluble PAEKs with high T_g by coordinating the relationship between chain rigidity resulting from the carbazole unit and chain distance from the side alkyl. © 2014 Society of Chemical Industry     

Design of polymers for migration imaging application II: Synthesis and polymerisation of p-isobutyl styrene

A copolymer series was synthesized for migration imaging applications from isobutyl methacrylate and isobutyl styrene such that each homopolymer and all copolymers had glass transition temperature (T_g) near 55°C. The T_g of poly (p-isobutylstyrene) was predicted from literature values of similar polymers to be near 55°C. Poly (p-isobutylstyrene) was synthesised by acetylation of isobutyl benzene, reduction of p-isobutylacetoph-enone to the carbinol, dehydration to p-isobutylstyrene and free radical polymerisation to the polymer. The T_g of the homopolymer was 55°C, in excellent agreement with the predicted value. Copolymers of isobutyl methacrylate and p-isobutyl styrene were synthesised and their T_g's measured across the series by DSC (57°C ± 5°C). refractive index temperature coefficient (42°C ± 5°C). The copolymer series was also characterised by melt viscosity measurements.     

Synthesis of polyundecamethylene 2,6‐naphthalamide as semiaromatic polyamide‐containing naphthalene ring

A novel engineering plastic polyundecamethylene 2,6‐naphthalamide (PA11N) was prepared via a reaction of 2,6‐naphthalene dicarboxylic acid and 1,11‐undecanediamine through a three‐step procedure. The structure of synthesized PA11N was characterized by elemental analysis, Fourier transform infrared spectroscopy, and proton nuclear magnetic resonance (¹H‐NMR). The thermal behaviors were determined by differential scanning calorimetry, thermogravimetric analysis, and dynamic mechanical analysis. The solubility, water‐absorbing capacity, and mechanical properties of PA11N have also been investigated. Melting temperature (T_m), glass transition temperature (T_g), and decomposition temperature (T_d) of PA11N are 294, 139, and 493°C, respectively. The results show that the heat resistance and mechanical properties of PA11N are near to those of polynonamethylene terephthalamide, and PA11N is a promising heat‐resistant and processable engineering plastic. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010