Methyl Α-hydroxymethylacrylate Research Articles

UV curable coatings for improved gas barrier properties of poly(ethylene terephthalate)

A new high-barrier coating based on methyl (α-hydroxymethyl)acrylate (MHMA) for poly(ethylene terephthalate) (PET) was developed along with the process for preform dipping and cure prior to blow molding into bottles. The UV curable coating gives excellent gas barrier improvement when coated onto PET biaxially oriented thin films. Blown bottle side walls from coated PET preforms also show 2–3 times improvement over uncoated side walls. The effect of photoinitiator concentration, initiator types, and temperature on photopolymerization kinetics of MHMA was investigated. Once the photoinitiator, Irgacure 819®, concentration became larger than 1mol%, a decrease in rate of propagation was observed. The conversion also decreased with higher initiator concentration. Irgacure 819® reduced the auto-acceleration peak and reached maximum rates of polymerization much faster than Irgacure 651®. It also gave a slightly higher conversion. Overall conversion for combinations of these photoinitiators was high, above 80%. Real-time FTIR (RT-FTIR) studies of copolymerization of MHMA and methyl methacrylate (MMA) showed that conversion was fairly high up to 25mol% MMA. However, once MMA feed ratio exceeded 10mol%, a decrease in barrier performance was observed.

A polymerizable photosensitizer and its photopolymerization kinetics

AbstractA previously reported polymerizable benzophenone photosensitizer, 2‐methacryloxyethyl 4‐benzoylbenzoate (MEBB), was synthesized and characterized. The photopolymerization kinetics of methyl α‐hydroxymethylacrylate (MHMA) and 1,6‐hexanediol diacrylate (HDDA) initiated with MEBB or benzophenone (BP) in the presence or absence of amine co‐initiators were determined by photo‐differential scanning calorimetry. The results indicate that benzophenone with a p‐carbonyl substitutent is more efficient in photoinitiation when compared to the non‐substituted benzophenone analogue. The final monomer conversions in the presence of amine co‐initiators are slightly higher than without them. Copyright © 2005 Society of Chemical Industry

Modeling the free radical polymerization of acrylates

AbstractAcrylates have gained importance because of their ease of conversion to high‐molecular‐weight polymers and their broad industrial use. Methyl methacrylate (MMA) is a well‐known monomer for free radical polymerization, but its α‐methyl substituent restricts the chemical modification of the monomer and therefore the properties of the resulting polymer. The presence of a heteroatom in the methyl group is known to increase the polymerizability of MMA. Methyl α‐hydroxymethylacrylate (MHMA), methyl α‐methoxymethylacrylate (MC1MA), methyl α‐acetoxymethylacrylate (MAcMA) show even better conversions to high‐molecular‐weight polymers than MMA. In contrast, the polymerization rate is known to decrease as the methyl group is replaced by ethyl in ethyl α‐hydroxymethylacrylate (EHMA) and t‐butyl in t‐butyl α‐hydroxymethylacrylate (TBHMA). In this study, quantum mechanical tools (B3LYP/6‐31G*) have been used in order to understand the mechanistic behavior of the free radical polymerization reactions of acrylates. The polymerization rates of MMA, MHMA, MC1MA, MAcMA, EHMA, TBHMA, MC1AN (α‐methoxymethyl acrylonitrile), and MC1AA (α‐methoxymethyl acrylic acid) have been evaluated and rationalized. Simple monomers such as allyl alcohol (AA) and allyl chloride (AC) have also been modeled for comparative purposes. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2005

Synthetic clay nanocomposite‐based coatings prepared by UV‐cure photopolymerization

AbstractThe effect of synthetic clay on the photopolymerization kinetics and coating properties of methyl α‐hydroxymethylacrylate (MHMA) systems in the presence of novel hydroxylated dimethacrylate crosslinkers is reported. In the presence of clay earlier onset of autoacceleration was observed, high rates of polymerization were achieved, and high final overall conversions were reached. Higher rates and increase in conversions were also observed as the clay content increased in the medium. To increase compatibility between clay and polymer matrix the use of Jeffamines as polymer/clay compatibilizers, based on ion–dipole interactions between ethylene oxide units and clay ions, was also investigated. Nanocomposite‐based films by photopolymerization of the mixtures coated on glass microscope slides were prepared and evaluated using X‐ray and TEM. The absence of Bragg diffraction peaks in all nanocomposite films indicated loss of organization of the clay layers and formation of well‐dispersed, exfoliated systems was confirmed by TEM. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 1252–1263, 2004

Synthesis and photopolymerization kinetics of new flexible diacrylate and dimethacrylate crosslinkers based on C18 diacid

A series of new di(meth)acrylate monomers was synthesized from the reactions of methyl α-hydroxymethylacrylate (MHMA), ethyl α-hydroxymethylacrylate (EHMA), hydroxyethyl acrylate (HEA) and hydroxyethylmethacrylate (HEMA) with α,ω-C18 diacid chloride. The photopolymerization behavior and reaction kinetics of the synthesized monomers were investigated using photoinitiation with differential scanning calorimetry. The polymerization rates, conversions and kinetic constants for propagation and termination were determined for each of the monomers. The maximum rate of polymerizations of the diacrylate monomers was higher than that of the dimethacrylate monomers and followed the order: HDDA (1,6-hexanediol diacrylate)>HEA-C18>EHMA-C18∼HEMA-C18>MHMA-C18. The total conversions obtained were 78, 75, 72, 64 and 69% for MHMA-C18, EHMA-C18, HEMA-C18, HEA-C18 and HDDA, respectively, indicating comparable or higher conversions for methacrylates despite their lower rates of polymerization. Propagation and termination mechanisms of the monomers were investigated by plotting propagation and termination rate constants as a function of conversion.

A Facile, Efficient Route to Methyl α-Hydroxymethylacrylate and Methyl α-Halomethylacrylates

Abstract DABCO-catalysed coupling of formaldehyde and methyl acrylate provides the title hydroxy compound. Treatment with HBr conveniently affords the key synthetic intermediate methyl α-bromomethylacrylate in good overall yield.