Preparation of novel UV-curable methacrylated urethane resins from a modified epoxy resin and isocyanatoethylmethacrylate (IEM)

Summary New UV curable methacrylated urethanes (PAPHEN-XIEM) were synthesized by substituting X percent (e.g., 10, 20, 30 %) of the total OH content of the PAPHEN-301 (Scheme 1) with isocyanatoethyl methacrylate (IEM). These resins were used alone (neat resin formulation) or as a mixture of 5, 10 and 13 % (w/w) respectively with methacrylated urethane prepolymer (PTHFUMA) in UV systems. For neat resin formulations, tensile strength and modulus values were observed to be inversely proportional with the modification degree of PAPHEN-301 as opposed to what is normally expected. This may be explained as a result of screening effect of increasing unsaturation. The water absorption capacities for neat resins and PTHFUMA-included formulations were decreased as the modification degree increased due to the replacement of hydrophilic OH groups of PAPHEN-301 by the hydrophobic methacrylate groups. TGA thermograms of neat resin formulation show that, initial weight loss temperatures are lower; possibly owing to the higher methacrylate content in the formulations. Received: 26 June 2001/Revised version: 5 April 2001/Accepted: 5 April 2001     

Biobased composites prepared by compression molding with a novel thermoset resin from soybean oil and a natural‐fiber reinforcement

Biobased composites were manufactured with a compression‐molding technique. Novel thermoset resins from soybean oil were used as a matrix, and flax fibers were used as reinforcements. The air‐laid fibers were stacked randomly, the woven fabrics were stacked crosswise (0/90°), and impregnation was performed manually. The fiber/resin ratio was 60 : 40. The prepared biobased composites were characterized by impact and flexural testing. Scanning electron microscopy of knife‐cut cross sections of the specimens was also done to investigate the fiber–matrix interface. Thermogravimetric analysis of the composites was carried out to provide indications of thermal stability. Three resins from soybean oil [methacrylated soybean oil, methacrylic anhydride modified soybean oil (MMSO), and acetic anhydride modified soybean oil] were used as matrices. The impact strength of the composites with MMSO resin reinforced with air‐laid flax fibers was 24 kJ/m², whereas that of the MMSO resin reinforced with woven flax fabric was between 24 and 29 kJ/m². The flexural strength of the MMSO resin reinforced with air‐laid flax fibers was between 83 and 118 MPa, and the flexural modulus was between 4 and 6 GPa, whereas the flexural strength of the MMSO resin reinforced with woven fabric was between 90 and 110 MPa, and the flexural modulus was between 4.87 and 6.1 GPa. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Synthesis and Polymerization of Epoxy Methacrylates, 2. Acylated Epoxy Methacrylates and their Copolymers

Partially (20–75%) acylated isopropylidene‐bis[1,4‐phenyleneoxy(2‐hydroxytrimethylene)] dimethacrylate (BisGMA) was prepared by a single step reaction of 2,2‐bis[4‐(2,3‐epoxypropoxy)phenyl]propane (DGEBA) with methacrylic acid (MAA), methacrylic anhydride (MAAn) and/or acetic anhydride catalyzed by 0.8 mol‐% N‐methylimidazole at 90–100°C. In any case, MAA was substituted by an equimolar quantity of the anhydride. The reaction kinetics of DGEBA with MAA and MAAn follows a first order law up to a conversion of epoxy groups corresponding to the initial molar ratio of MAAn. For different mole fractions x_MAA, the reaction rate was found to be directly proportional to x^0.5_MAA. The viscosity of BisGMA decreased with an increase in the acylation degree. Acylated BisGMA was copolymerized with triethylene glycol dimethacrylate (TEGMA) by use of a redox initiator system at room temperature and with vinyltoluene (VT) initiated by di‐tert‐butyl peroxide at 150–200°C, respectively, both in the presence of 70–76 wt.‐% of quartz filler. Different dependencies of the content of sol and the conversion of C=C double bonds were observed for thermally polymerized composites from VT with acetylated and methacrylated BisGMA, respectively. Methacrylated BisGMA yielded composites with reduced water uptake. The higher network density of the polymer matrix with methacrylated BisGMA resulted in a higher glass transition temperature T_g and a higher storage modulus of the composites. The initial temperature of weight loss of composites with VT was increased from 230°C for composites with BisGMA up to 258°C for composites with BisGMA methacrylated to a degree of 40%.     

Synthesis,characterization, and cure of allyl and propargyl functionalized indene as a thermoset composite matrix resin

Two highly functionalized resins were synthesized by the phase transfer reaction of indene with propargyl bromide or allyl chloride in the presence of strong base. The resins consisted of a mixture of tri- and tetrafunctional indenes with 60–80% of the product being tetrafunctional. The allylated (AL) and propargylated (PL) indene resins were thermally cured without added catalysts. Both resins exhibited a broad, highly exothermic cure with a peak energy at 320°C for AL resin and 282°C for PL resin. Thermal degradation of cured AL resin was found to begin at approximately 400°C with a carbon yield of 20% of its initial weight at 1000°C. Carbon yields for cured PL resin were excellent, with 68% retention of weight at 1000°C. Unidirectional, carbon fiber composites were fabricated from the substituted indene resins. AL–carbon fiber composites gave modulus values of 126 GPa and strength values of 967 MPa, while PL–carbon fiber composites gave modulus values of 116 GPa and strength values of 935 MPa in three-point bending tests. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 68: 475–482, 1998     

Poly(propylene oxide) Modified Dimethacrylate Networks

A series of methacrylated poly(propylene oxide)/reduced styrene content/dimethacrylate resin systems have been prepared. These modified vinyl esters may be ideal for coatings, toughened matrix resins for fiber-reinforced composites, bridge deck wear surface resins, and structural adhesive applications. Network systems cured with room-temperature and elevated-temperature cure methods have been studied. The network morphologies were investigated by DMA and TEM analyses. The K_1c values of the adhesives increases when systems were cured with the room-temperature cure package. The lap-shear strength of these systems were investigated for structures including composite-to-composite, composite-to-steel, and composite-to-concrete following ASTM D1002. Lap-shear adhesive strengths of all of the adhesives, which had appropriate viscosities on composite substrates, were in the structural regime with values of ∼13.8 MPa. Room-temperature cure schedules (with and without a postcure) resulted in good adhesive strength on the composite and aluminum substrates, displaying values up to 15.2 MPa.     

Synthesis and characterization of melt‐processable polyimides derived from 1,4‐bis(4‐amino‐2‐trifluoromethylphenoxy)benzene

A series of molecular‐weight‐controlled imide resins end‐capped with phenylethynyl groups were prepared through the polycondensation of a mixture of 1,4‐bis(4‐amino‐2‐trifluoromethylphenoxy)benzene and 1,3‐bis(4‐aminophenoxy)benzene with 4,4′‐oxydiphthalic anhydride in the presence of 4‐phenylethynylphthalic anhydride as an end‐capping agent. The effects of the resin chemical structures and molecular weights on their melt processability and thermal properties were systematically investigated. The experimental results demonstrated that the molecular‐weight‐controlled imide resins exhibited not only meltability and melt stability but also low melt viscosity and high fluidability at temperatures lower than 280°C. The molecular‐weight‐controlled imide resins could be thermally cured at 371°C to yield thermoset polyimides by polymer chain extension and crosslinking. The neat thermoset polyimides showed excellent thermal stability, with an initial thermal decomposition temperature of more than 500°C and high glass‐transition temperatures greater than 290°C, and good mechanical properties, with flexural strengths in the range of 140.1–163.6 MPa, flexural moduli of 3.0–3.6 GPa, tensile strengths of 60.7–93.8 MPa, and elongations at break as high as 14.7%. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2008     

Effects of various additives on the performance of bis‐GMA/barium glass powder composites

The effects of various additives on the performance of 2,2′‐bis[4‐(methacryloxy‐2‐hydroxy‐propoxy)‐phenyl]‐propane (Bis‐GMA)/barium glass powder (Ba) composites were examined. Bis‐GMA/Ba composites were manufactured by curing with visible light to measure various mechanical properties. The diametral tensile strengths (DTS) of Bis‐GMA/Ba composites were the primary focus of this investigation. The main additives used were trimethylolpropyltrimethacrylate (TMPT), 1,4‐bis‐(tri‐methoxysilylethyl) benzene (BTB), and cationic styryl silane. These additives were applied as both integral blends and aqueous pretreatments. Besides the DTS, Vickers hardness of cured matrix resins and the viscosity of composite pastes were measured to study the properties of the matrix resins and the processibility of the composites, respectively. Integral blends showed similar processibility to aqueous pretreatments. The addition of TMPT to the matrix resins increased Vickers hardness of integral blend systems as a result of its trimethacrylate functional group. BTB was useful in increasing the wet DTS of Bis‐GMA/silane–treated Ba composites. STS was effective in improving the performance of Bis‐GMA/Ba composites in the cases of both the integral blends and aqueous pretreatments. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 76: 1085–1092, 2000     

Poly(propylene oxide) Modified Dimethacrylate Networks

A series of methacrylated poly(propylene oxide)/reduced styrene content/dimethacrylate resin systems have been prepared. These modified vinyl esters may be ideal for coatings, toughened matrix resins for fiber-reinforced composites, bridge deck wear surface resins, and structural adhesive applications. Network systems cured with room-temperature and elevated-temperature cure methods have been studied. The network morphologies were investigated by DMA and TEM analyses. The K_1c values of the adhesives increases when systems were cured with the room-temperature cure package. The lap-shear strength of these systems were investigated for structures including composite-to-composite, composite-to-steel, and composite-to-concrete following ASTM D1002. Lap-shear adhesive strengths of all of the adhesives, which had appropriate viscosities on composite substrates, were in the structural regime with values of ～13.8 MPa. Room-temperature cure schedules (with and without a postcure) resulted in good adhesive strength on the composite and aluminum substrates, displaying values up to 15.2 MPa.     

Utilization of Recycled Polypropylene for Production of Eco-Composites

Renewable raw materials and recyclable thermoplastic polymers provide attractive eco-friendly quality as well as environmental sustainability to the resulting natural fiber reinforced composites. We studied the possibility of using the recycled polypropylene (PP) for production of composites based on kenaf fibers (KF) and rice hulls (RH) as reinforcements. Polypropylene/rice-hulls (PP/RH/CA) and polypropylene/kenaf (PP/K/CA) composites with 30% fiber (filler) content and appropriate compatibilizing agent (CA)—a maleic anhydride grafted PP (MAPP), have been prepared by two steps procedure: melt mixing and compression molding. Flexural strength and thermal stability of the composites with recycled PP were similar to those with neat PP. The composites reinforced with kenaf fibers have shown better properties than those based on rice hulls. The flexural strength of the composite sample with recycled PP is 51.3 MPa in comparison with 51.1 MPa for the composite with neat PP. Degradation temperatures of neat and composite with recycled PP at residual weight 90% are 344.4°C and 343.5°C, respectively. The results obtained report the possibility of utilization of recycled PP for the production of natural reinforcements based composites with good mechanical characteristics for using as construction building materials in housing systems.     

Tensile properties and stress whitening of polypropylene/polyolefin elastomer/magnesium hydroxide flame retardant composites for cable insulating application

Flame retardant polypropylene (PP) composites were prepared by combining random polypropylene with uncoated and surface‐treated forms of magnesium hydroxide filler and elastomeric modifiers, with and without maleic anhydride functionalization. Four types of magnesium hydroxide (MDH) with different surface treatments were compounded at amounts up to 60% by weight to PP/polyolefin elastomer (POE) matrix resin to obtain a series of composites. The tensile strength and elongation at break were measured. MDH coated with polymeric material was found to give a high elongation at break value compared with the values obtained with uncoated and vinyl silane and amino silane coated MDH. Two types of POE, i.e., neat and maleic anhydride grafted POE (POEgMA), were used to investigate the stress whitening of composites in bending deformation. POEgMA used composites showed no stress whitening while neat POE used composites showed whitening when bended. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 2311–2318, 2005     

Effects of diluent's concentration upon the properties of organically modified ceramics based composites for application in dentistry

Organically modified ceramic resin (ormoresin) mixed with triethylene glycol dimethacrylate (TEGDMA) was used as the binder resin for the preparation of visible light cured dental composite. Three different combinations of ormoresin and TEGDMA were used for the preparation of composites, and their properties were compared in terms of depth of cure, diametral tensile strength (DTS), flexural strength (FS), flexural modulus (FM), Vickers micro hardness (VMH), water sorption (WS), and solubility. It is found that an optimum amount of diluent is necessary for better crosslinking and properties of cured composites based on ormoresin. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 469–473, 2004     

Wood Plastic Composites Produced from Postconsumer Recycled Polystyrene and Coconut Shell: Effect of Coupling Agent and Processing Aid on Tensile,Thermal, and Morphological Properties

Expanded polystyrene (EPS) has been widely used as a disposable packaging material in many industries thanks to properties like low density, lightweight, high impact, and vibration damping. Although usage of EPS increases annually, recycling facilities often refused to process postconsumed EPS due to the poor economic viability associated with high logistics and transportation cost in collection, storage, and shipment of the material. The objective of this research is to enhance the value chain of postconsumed EPS by investigating its potential as feedstock in the development of sustainable wood plastic composites (WPC), thereby providing an attractive business opportunity that also increases interest in EPS recycling and indirectly continue the lifespan of disposed EPS. Varying compositions of recycled polystyrene (rPS), coconut shell (CS), maleated polystyrene (MAPS) and Ultra-Plast WP516 were compounded using a HAAKE internal mixer and compression molded to form WPC. The effects of material formulation on mechanical, thermal, and morphological properties of the composites were studied. The experiment showed that WPC formulated with 100 phr of rPS, 30 phr of CS, 3 phr of MAPS, and 1 phr of Ultra-Plast WP516 possesses higher modulus and tensile strength compared to the neat EPS, measured at 2.5 GPa and 27.5 MPa, respectively. Although the WPC experienced initiation of thermal degradation at a temperature lower than neat rPS, but the thermal stability of rPS/CS composites containing varying composition of MAPS and Ultra-Plast WP516 was better at high temperature. Furthermore, a 50% weight loss took place at a higher temperature. Nevertheless, the glass transition temperature of the rPS/CS composite with addition of MAPS and Ultra-Plast WP516 was found lower than the neat rPS. POLYM. ENG. SCI., 60:202–210, 2020. © 2019 Society of Plastics Engineers     

Evaluation of monomers derived from resorcinol as eluents of bisphenol A glycidyl dimethacrylate for the formulation of dental composite resins

The objective of this work was to synthesize two bio-based monomers, using the resorcinol as raw material, and its effect as bisphenol A glycidyl dimethacrylate (Bis-GMA) eluents on different chemical–physical and biological properties of experimental photopolymerizable composite resins. The acrylic 1,3-phenylen diacrylic (1,3-FDA) and methacrylic 1,3-phenylen dimethacrylic (1,3-FDMA) monomers were synthesized and fully characterized through FTIR and ¹H-NMR spectroscopies. Experimental photopolimerizable composites were formulated using Bis-GMA/1,3-FDA or Bis-GMA/1,3-FDMA as organic matrix. The materials were compared with a Bis-GMA/TEGDMA resin-based composite used as control. Polymerization kinetics was evaluated by means of FTIR spectroscopy. Polymerization stress was directly measured through a polymerization stress tester. The cell viability of the composites was evaluated using the MTT assay. One-way analysis of variance and Tukey's test were used for statistical analysis. The materials formulated with the 1,3-FDA monomer showed higher Rp_max values and lower polymerization stress values (p < 0.05), while the flexural strength, water sorption, and solubility remained similar to the TEGDMA composite. Conversely, the materials formulated with the 1,3-FDMA monomer showed a lower degree of conversion and statistically lower flexural strength (p < 0.05). All materials exhibited a cellular viability close to 100%. Concerning the study conditions, the acrylic 1,3-FDA monomer could be considered an alternative to TEGDMA in the formulation of photopolymerizable dental composite resins. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48576.     

Synthesis of reactive soybean oils for use as a biobased thermoset resins in structural natural fiber composites

Biobased thermosets resins were synthesized by functionalizing the triglycerides of epoxidized soybean oil with methacrylic acid, acetyl anhydride, and methacrylic anhydride. The obtained resins were characterized with FTIR, ¹H‐NMR, and ¹³C‐NMR spectroscopy to confirm the functionalization reactions and the extent of epoxy conversion. The viscosities of the methacrylated soybean oil resins were also measured for the purpose of being used as a matrix in composite applications. The cross‐linking capability was estimated by UV and thermally initiated curing experiments, and by DSC analysis regarding the degree of crosslinking. The modifications were successful because up to 97% conversion of epoxy group were achieved leaving only 2.2% of unreacted epoxy groups, which was confirmed by ¹H‐NMR. The ¹³C‐NMR confirms the ratio of acetate to methacrylate methyl group to be 1 : 1. The viscosities of the methacrylated soybean oil (MSO) and methacrylic anhydride modified soybean oil (MMSO) were 0.2 and 0.48 Pas, respectively, which indicates that they can be used in resin transfer molding process. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

The effect of grafted caged silica (polyhedral oligomeric silesquioxanes) on the properties of dental composites and adhesives

With the emergence of commercial grafted caged silica (Polyhedral Oligomeric Silesquioxanes, POSS) having a three-dimensional (3D) morphology with peripheral functionality, new opportunities have been created for formulating dental adhesives and composites with enhanced mechanical and physical properties. The objective of the present study was to investigate the properties obtained by incorporating grafted caged silica into acrylate based dental composite and adhesive systems. Two commercial POSS materials (methacrylated and octaphenyl grafted) were added to dental restorative-glass-filled pre-polymers, based on BisGMA (bis-phenol A-glycidyldimethacrylate), HEMA (2-hydroxyethylmethacrylate) and TEGDMA (tetraethylglycidylmethacrylate). The nanostructured organic/inorganic hybrid compounds exhibited enhanced mechanical and thermal properties in cases where the POSS added was in concentrations up to 2 wt%. Beyond this threshold concentration, properties decreased due to agglomeration. In the case of the acrylated POSS, the T _g increased by 5°C, the composite compressive strength by 7%, and the bond shear strength by 36% and the shrinkage was reduced by 28% compared with neat dental composites and adhesives. Furthermore, in the case of octaphenyl grafted POSS, the compressive strength was reduced by 20%, the adhesive shear bond strength decreased by 49% and the shrinkage was reduced by 67%. It was concluded that the type of the grafted functional group of the caged silica was the dominant factor in nano-tailoring of improved dental composites and adhesives.     

Sunflower seed cake as reinforcing filler in thermoplastic composites

Dimensional stability, mechanical properties, and melting and crystallization behavior of polypropylene composites filled with sunflower seed cake (SSC) were investigated. Injection molded composites were prepared from the SSC flour and polypropylene with and without maleic anhydride‐grafted polypropylene (MAPP) at 30, 40, 50, and 60 wt % contents of the SSC flour. Twenty‐eight days thickness swelling and water absorption values of the specimens increased by 43 and 56% as the filler content increased from 30 to 60 wt %, respectively. The flexural modulus of the polypropylene composites increased from 3157 to 4363 MPa as the SSC flour increased from 30 to 60 wt %. The maximum flexural strength 38.4 MPa was observed for 40 wt % SSC flour filled specimens. However, further increment in the SCC flour decreased the flexural strength to 31.4 MPa. The tensile strength of the specimens decreased from 22.5 to 14 MPa while the tensile modulus increased from 3023 to 3677 MPa as the SSC flour increased from 30 to 60 wt %. The dimensional stability and mechanical properties of the composites were significantly improved by the incorporation of the coupling agent (MAPP). The effect of the MAPP addition was more pronounced for the strength than for the modulus. The melting temperature and degree of crystallinity of the neat polypropylene decreased with increasing content of the SSC flour. The degree of crystallinity of filled composites considerably increased with the incorporation of the MAPP. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

双酰亚胺类蛋白质荧光探针的合成

以6种N 取代 4 氨基 邻苯二甲酰亚胺及马来酸酐为起始原料合成了相应的6种N (N 取代 邻苯二甲酰亚胺 4 基) 马来酰亚胺(Ⅱ)。丙酮为溶剂,氮气保护,室温下N 取代 4 氨基 邻苯二甲酰亚胺及马来酸酐反应2 5h得到N (N 取代 邻苯二甲酰亚胺 4 基) 氨基马来酰酸(Ⅰ),收率均>90%。Ⅰ在三乙胺与乙酐作用下,脱水环合生成N (N 取代 邻苯二甲酰亚胺 4 基) 马来酰亚胺(Ⅱ),反应收率达69%～85%。各步产物经1HNMR、IR确定结构。在研究脱水环合反应的过程中,分离得到其中一种产物的反应中间体:N (N 丁基 邻苯二甲酰亚胺 4 基) 氨基马来酰酸乙酸酐(Ⅲ),由此推测该反应为五元环过渡态的SN2亲核取代机理。     

Graphene oxide–polyoctahedral silsesquioxane–chitosan composite films with improved mechanical and water-vapor-transport properties

Graphene oxide (GO) and ball-milled maleamic acid–isobutyl polyoctahedral silsesquioxanes (MAIPSs) were incorporated simultaneously into chitosan (CS) via solution blending to evaluate their combined effects on the structures and properties of composite films. GO and MAIPS aggregates were homogeneously dispersed in CS and affected the crystallinities of the composite films. The binary addition of GO and MAIPS resulted in synergistic enhancements of the tensile strength and elongation at break of the composite films. Composite films containing 3% w/w MAIPS and 0.25% w/w GO (CS–GO–MAIPS-3) exhibited the highest strength and modulus, which were 48 and 42.2% higher, respectively, than the values of the CS film. The water-vapor-sorption isotherms revealed that monolayer sorption sites decreased with the addition of GO or/and MAIPS, but the dissolution process was not significantly influenced. The water-vapor permeability reached its lowest value for the CS–GO–MAIPS-3 film because of hindered diffusion with the presence of impermeable nanoparticles. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47748.     

马来酸酐接枝聚丙烯对亚麻纤维增强高密度聚乙烯力学性能影响

通过双螺杆挤出造粒,制备了亚麻纤维增强高密度聚乙烯（PE-HD）复合材料,研究了相容剂马来酸酐接枝聚丙烯（PP-g-MAH）含量对于复合材料性能改善的效果。结果表明：复合材料力学性能得到了显著的提升,其中拉伸强度、弯曲强度和冲击强度最大值分别为32.75、37.21、43 kJ/m2;PP-g-MAH含量为5 ％或者10 ％时复合材料具有相对较好的力学性能;PP-g-MAH的加入能提高复合材料的耐热性,降低复合材料力学损耗。     

On the Use of Surfactant-Complexed Chitosan for Toughening 3D Printed Polymethacrylate Composites

This work reports a simple approach to prepare toughened 3D-printed polymethacrylate (PMA) composites using surfactant-modified chitosan (SMCS) particles at loadings between 2–10 wt%. Chitosan (CS) is modified with anionic surfactant, sodium dodecyl sulfate, via ionic complexation to facilitate compatibility and dispersion of CS to PMA matrix by non-covalent interactions between the components. The study successfully demonstrates high-accuracy 3D printing of composites with significant improvements in the overall mechanical properties. The composite with the best loading of 8 wt% SMCS shows a tensile modulus of 1.23 ± 0.05 GPa, a tensile strength at 49.8 ± 0.96 MPa, a yield stress at 33.3 ± 1.48 MPa, and a strain-at-failure 10.3 ± 0.61%, which are 45%, 40%, 32%, and 68% higher than neat PMA, respectively. This provides a significant improvement in toughness at 4.92 ± 0.55 MJ m⁻³ for the composite, 184% higher than that of neat PMA. The marked increase in toughness is due to enhanced filler-matrix interactions which improve the ability of the 3D printed composite to absorb energy under tensile load. The results from this work provide new understandings into the strategies for design and preparation of stereolithography 3D printed materials reinforced with toughening fillers from renewable resources.