Acrylate Double Bonds Research Articles

UV curing of aqueous polyurethane acrylate dispersions. A comparative study by real-time FTIR spectroscopy and pilot scale curing

Real-time FTIR spectroscopy was used to study the chemical and physical factors, e.g., photoinitiator and temperature, affecting the UV curing of dried films from aqueous polyurethane acrylate dispersions. Poor conversion of the acrylate double bonds (67%) observed at room temperature can be overcome by irradiation at elevated temperatures. At 353 K almost complete conversion is observed, even with reduced photoinitiator content. Single or multiple UV-light flash experiments were performed to simulate technical parameters, e.g., cure speed and number of required UV lamps, with the help of RTIR spectroscopy. The results obtained were confirmed by pilot-scale UV curing experiments: one or, at most, two UV lamps of high intensity are sufficient for the curing process with respect to the double-bond conversion. The coatings based on the polyurethane acrylate dispersion show low sensitivity towards oxygen from air. Moreover, in comparison to UV curing under inert nitrogen atmosphere, a small “positive” effect on the conversion in the presence of air has been observed, which might be due to the contribution of peroxyl radicals or their decomposition products to curing.

Ultraviolet-curable liquid natural rubber

Preparation of ultraviolet (UV)-curable liquid natural rubber was achieved by fixation of photosensitive molecule onto liquid natural rubber. The liquid natural rubber (LNR) was prepared by oxidative degradation of natural rubber latex, using the phenylhydrazine/O2 system. The LNR was further treated with in situ performic acid, which leads to epoxidized liquid natural rubber (ELNR). The progress of the addition reaction of photosensitive acrylic acid onto epoxide ring of the ELNR was followed by infrared spectroscopy. It was found that at 80°C reaction temperature, epoxide ring opening reaction of ELNR came to completion within 2 h, which is faster than the reaction at 60°C. The photocrosslinking reaction of the acrylated ELNR was studied by monitoring the exothermic heat of photocuring of acrylate double bond using a double beam photocalorimeter (DPA7). It was found that the fast crosslinking-polymerization occurred when the rubber was exposed to UV irradiation in the presence of photocleavage initiator (Irgacure 184 and Darocur 1173) and liquid diacrylate monomer (1,6 hexanediol diacrylate and tripropylene glycol diacrylate). The cure kinetics of the elastomers were also investigated, and it was found that the diacrylate monomer, photoinitiator concentration play an important role on the rate and extent of the reaction. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 78: 1478–1485, 2000

Recent developments in photoinitiated radical polymerization

AbstractThis article presents the progress made in the development of high‐speed photocurable resins and reports the performance of some novel radical‐type photoinitiators, acrylate monomers and telechelic oligomers. The polymerization kinetics has been studied by real‐time infrared spectroscopy, which records conversion versus time curves for reactions occurring in a fraction of a second. Phosphine oxides are among the most efficient photoinitiators and proved to be particularly well suited for the photocuring of pigmented systems and for solar‐assisted polymerization. Acrylate monomers containing a heterocyclic oxygen in their structural unit exhibit an unexpectedly high reactivity. The introduction of an amino group in the chain of a telechelic acrylate‐polyester causes a substantial acceleration of the polymerization process. In both cases, the increase in reactivity was attributed to the presence of labile hydrogen atoms which favor chain transfer reactions. The copolymerization of donor‐acceptor monomer systems, like vinyl ether‐maleate or vinyl ether maleimide, was shown to proceed readily upon UV irradiation, even in the absence of added photoinitiator. Light‐induced polymerization was also used to crosslink rapidly polymers functionalized with acrylate or vinyl double bonds, namely acrylated polyisoprene and a styrene‐butadiene block copolymer. The addition in small amounts (1 wt%) of a trifunctional thiol was found to speed up drastically the crosslinking polymerization, causing insolubilization of the thermoplastic elastomer to occur after a 0.1 s exposure.

UV curing of surface coating system consisting of cycloaliphatic diepoxide-ENR-glycidyl methacrylate by cationic photoinitiators?characterization of the cured film by FTIR spectroscopy

This paper reports the results of spectroscopic investigations carried out on film cast from a system consisting of cycloaliphatic diepoxide, epoxidized natural rubber (ENR-50), and glycidyl methacrylate (GMA) and cured by the UV radiation. GMA acts as a reactive diluent for the ENR. Triphenyl sulphonium hexafluoro antimonate was used as the cationic photoinitiator. Results reported in a previous paper showed that ENR acts as a toughening agent. Optical microscopic studies were suggestive of the existence of two-phase morphology consisting of an elastomeric domain and the resin matrix domain. For effective toughening, it is essential that good adhesion exists between these two domains. It was of interest, therefore, to know whether favorable interactions occurred between the different components of the coating systems employed in our studies to promote effective adhesion between the elastomeric domain and the resin matrix. Systematic spectral studies were, therefore, conducted with a view to understanding how different components of the hybrid coating system interact. The results showed that the acrylic double bonds, as well as the epoxy groups of GMA, the isoprene double bonds and epoxy groups of ENR, and the epoxy groups of cycloaliphatic epoxide resin all participate in a scheme of photoinitiated polymerization and crosslinking reactions ultimately producing an interpenetrating polymer network, a result conducive to effective toughening of the epoxy resins, which are intrinsically brittle. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 73: 1569–1577, 1999

Photocrosslinking of functionalized rubbers, 7. Styrene-butadiene block copolymers

The photocrosslinking of polystyrene-block-polybutadiene-block-polystyrene (SBS) was studied by means of infrared spectroscopy, by monitoring the disappearance of the pendent vinyl double bonds, which was shown to proceed within a few seconds upon UV exposure in the presence of an acylphosphine oxide photoinitiator. Complete insolubilization requires the reaction of 17 double bonds per polymer chain for an SBS sample containing 8% vinyl groups. An increase of the vinyl content has little effect on the crosslinking process, because it enhances mainly intramolecular reactions. A paraffinic oil proved to be an effective plasticizer for the photocrosslinked elastomer. The addition of a telechelic acrylate oligomer causes a substantial increase of both the reaction rate and the final degree of conversion of the SBS double bonds. The light-induced copolymerization of the vinyl and butene double bonds with the acrylate double bonds leads to the formation of a hard and flexible polymer material within a fraction of a second.

Photocrosslinking of functionalized rubbers, 7. Styrene-butadiene block copolymers

The photocrosslinking of polystyrene-block-polybutadiene-block-polystyrene (SBS) was studied by means of infrared spectroscopy, by monitoring the disappearance of the pendent vinyl double bonds, which was shown to proceed within a few seconds upon UV exposure in the presence of an acylphosphine oxide photoinitiator. Complete insolubilization requires the reaction of 17 double bonds per polymer chain for an SBS sample containing 8% vinyl groups. An increase of the vinyl content has little effect on the crosslinking process, because it enhances mainly intramolecular reactions. A paraffinic oil proved to be an effective plasticizer for the photocrosslinked elastomer. The addition of a telechelic acrylate oligomer causes a substantial increase of both the reaction rate and the final degree of conversion of the SBS double bonds. The light-induced copolymerization of the vinyl and butene double bonds with the acrylate double bonds leads to the formation of a hard and flexible polymer material within a fraction of a second.

Radical generation from photoinitiator (IC 2959) decomposition and radical addition to acrylate. A laser photolysis Fourier transform electron paramagnetic resonance study

The decomposition of the photoinitiator 1-[4-(2-hydroxyethoxy)phenyl]-2-hydroxy-2-methylpropan-1-one (trade name IC 2959) was studied using time-resolved laser photolysis Fourier transform electron paramagnetic resonance. The emissive CIDEP polarization of both benzoyl and 2-hydroxy-2-propyl radicals indicates the triplet state of IC 2959 as the radical precursor. By adding n-butyl acrylate it was shown that the addition of 2-hydroxy-2-propyl radicals to the acrylate double bond is two orders of magnitude faster than that of benzoyl radicals.

Light-stabilization of polymeric materials by grafted UV-cured coatings

The weathering resistance of organic materials has been substantially increased by protecting their surface with a photocured coating containing both a UV absorber (UVA) and a radical scavenger (HALS). A kinetic study by real-time IR spectroscopy has shown that HALS have no effect on the cure rate, whereas UV absorbers slow down the cure process, due to their radiation inner filter effect. 3D analysis of the depth of cure profile revealed an incomplete cure at the coating/substrate interface, leading to adhesion failure. To prevent this detrimental effect, the UV-cured coating was photochemically grafted onto the substrate. The polymer material was first coated with a thin layer of a benzophenone solution in a diacrylate monomer. Polymer radicals, generated by hydrogen abstraction from the substrate by the excited benzophenone molecules, effectively initiate the polymerization of the acrylate functions, thus ensuring a chemical bonding between the coating and the substrate. The grafting reaction was characterized by ATR spectroscopy analysis and by surface energy measurements. Excellent adhesion was achieved by applying to the treated substrate a photocurable acrylate coating, containing the light stabilizers, because of the copolymerization reaction taking place with the unreacted acrylate double bonds of the base coat, upon UV exposure. The efficiency of this on-line stabilization process has been demonstrated on poly(vinyl chloride) that was made eight times more resistant to accelerated weathering. © 1998 John Wiley & Sons, Inc. J. Polym. Sci. A Polym. Chem. 36: 2571–2580, 1998

Synthesis of poly(propylene-glycol-diacrylates) and properties of the photocured networks

A series of poly(propylene-glycol-diacrylates) (PPGDA) having molecular weights (MW) in the range 300–3,000 and an acrylic functionality near to two were synthesized by acrylation of the corresponding hydroxy-terminated oligomers with acrylic acid in the presence of p-toluensulphonic acid as a catalyst. The M¯n of the acrylated products was found slightly lower than that of the starting oligomers, indicating the occurrence of an acidic degradation reaction which does not influence the acrylic functionality. The acrylated oligomers were ultraviolet (UV) cured until a complete double bond disappearance was obtained: only in the presence of tripropylene-glycol-diacrylate (TPGDA) were small amounts of residual unsaturations revealed. Rubbery materials were usually obtained, with the exception of TPGDA. The properties of the cured PPGDA were investigated by means of differential scanning calorimetry, thermomechanical analysis, and dynamic mechanical thermal analysis. The Tg values were found to decrease by increasing the MW of the used oligomers, that is, by increasing the length of the chain between the two acrylic double bonds. A good agreement with the Nielsen equation was found. Moreover, the equilibrium swelling values in water were measured; the obtained values were interpreted in terms of the solubility parameters of the oligomers and of the crosslinking density of the networks. Finally, some mixtures of PPGDA oligomers with a typical epoxy-acrylate resin were UV cured; their properties confirm the high flexibilizing effect of the PPGDA oligomers. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 65:491–497, 1997

Vinyl monomers bearing chromophore moieties and their polymers. VI. Synthesis and photochemical behavior of acrylic monomer bearing phenoxazine moiety and its polymer

An acrylic monomer having phenoxazine moiety, i.e., N-acryloylphenoxazine (APO), has been synthesized by dehydrochlorination of N-(3-chloropropionyl)phenoxazine with 1,5-diazabicyclo[5.4.0]undec-5-ene in dimethyl sulfoxide. The monomer can be polymerized with AIBN as an initiator. The photochemical behavior, including the fluorescence and photosensitizing properties of this monomer and its polymer, has been studied. It has been recorded that the absorption spectrum of polymer P(APO) displays a few blue shifts compared with its monomer APO. It has also been observed that the fluorescence emission intensity of the monomer is dramatically lower than that of its polymer at the same chromophore concentration. This may be ascribed to the charge transfer interacting between the coexisting electron-accepting acrylic carbon-carbon double bond and the electron-donation phenoxazine moiety in APO, intramolecularly or intermolecularly on excitation. The fluorescence of the APO polymer, which does not have carbon-carbon double bond, can be quenched by electron-deficient unsaturated nitriles and esters, clarifying that the electron-deficient carbon-carbon double bond does play an important role for the fluorescence quenching of the monomer. Thus, we term such phenomena as structural self-quenching effect, differing from the concentrational self-quenching effect, which is caused mainly by concentrational factors. The fluorescence quenching of P(APO) by C60 has also been demonstrated. The formation of the charge transfer complex of P(APO) with C60 in the ground state is revealed by the upward deviation from the linearity of the Stern-Volmer plot. APO can act as a photoinitiator to sensitize the photopolymerization of vinyl monomers such as acrylonitrile in dimethyl formamide and pursued kinetically. From the ultraviolet analysis of the PAN sensitized by APO, it is proved that APO not only sensitizes the photopolymerization of AN, but also incorporates in the PAN chain. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 65:481–489, 1997

Vinyl monomers bearing chromophore moieties and their polymers. VI. Synthesis and photochemical behavior of acrylic monomer bearing phenoxazine moiety and its polymer

An acrylic monomer having phenoxazine moiety, i.e., N-acryloylphenoxazine (APO), has been synthesized by dehydrochlorination of N-(3-chloropropionyl)phenoxazine with 1,5-diazabicyclo[5.4.0]undec-5-ene in dimethyl sulfoxide. The monomer can be polymerized with AIBN as an initiator. The photochemical behavior, including the fluorescence and photosensitizing properties of this monomer and its polymer, has been studied. It has been recorded that the absorption spectrum of polymer P(APO) displays a few blue shifts compared with its monomer APO. It has also been observed that the fluorescence emission intensity of the monomer is dramatically lower than that of its polymer at the same chromophore concentration. This may be ascribed to the charge transfer interacting between the coexisting electron-accepting acrylic carbon-carbon double bond and the electron-donation phenoxazine moiety in APO, intramolecularly or intermolecularly on excitation. The fluorescence of the APO polymer, which does not have carbon-carbon double bond, can be quenched by electron-deficient unsaturated nitriles and esters, clarifying that the electron-deficient carbon-carbon double bond does play an important role for the fluorescence quenching of the monomer. Thus, we term such phenomena as structural self-quenching effect, differing from the concentrational self-quenching effect, which is caused mainly by concentrational factors. The fluorescence quenching of P(APO) by C60 has also been demonstrated. The formation of the charge transfer complex of P(APO) with C60 in the ground state is revealed by the upward deviation from the linearity of the Stern-Volmer plot. APO can act as a photoinitiator to sensitize the photopolymerization of vinyl monomers such as acrylonitrile in dimethyl formamide and pursued kinetically. From the ultraviolet analysis of the PAN sensitized by APO, it is proved that APO not only sensitizes the photopolymerization of AN, but also incorporates in the PAN chain. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 65:481–489, 1997

Photoinitiated Polymerization of Vinyl Ether and Acrylate Monomer Mixtures

The photoinitiated cationic polymerization of vinyl ether (VE) monomers has been studied by real-time infrared spectroscopy. For the divinyl ether of triethylene glycol, the chain reaction was shown to develop rapidly and extensively, with kinetic chain lengths on the order of 10,000. Interpenetrating polymer networks have been produced by UV curing of a vinyl ether/acrylate mixture in the presence of a cationic photoinitiator. The acrylate double bond polymerizes faster than the vinyl ether double bond and reaches 95% conversion in triacrylate monomers. Vinyl ether/acrylate hybrids were also found to polymerize readily upon UV exposure in the presence of a radical photoinitiator, according to a cross-propagation mechanism which generates a copolymer with isolated VE units. Acrylate radicals were shown to be twice as reactive toward the acrylate double bond than toward the vinyl ether double bond, thus leading to a UV-cured polymer which contains a relatively large amount of unreacted double bonds. The residual unsaturation content was markedly reduced by the addition of a cationic photoinitiator and by exposing the sample successively to filtered and unfiltered UV radiation.

Group Selective Linear Polymerization of Vinyl Acrylate Using19-Borabicyclo[3.3.1]nonane

Vinyl acrylate (VA) was polymerized with 9-borabicyclo[3.3.1]nonane (9-BBN) in tetrahydrofuran under argon at low temperatures (to -60°C). Hydroquinone and 2,6-di-tert-butyl-p-cresol had little effect on the polymerization. Addition of tetrachloromethane as a radical chain transfer agent did not lead to decrease in molecular weight of the polymer obtained. The initial rate of polymerization was proportional to [9-BBN]0·91 and [VA]1·37. The experimental results were indicative of non-radical properties of the propagating chain end. The polymer was soluble in organic solvents such as toluene, chloroform and N,N-dimethylformamide. The nuclear magnetic resonance measurements showed the presence of pendant vinyl groups in the polymer, indicating that only the acrylic double bond of VA reacted for polymerization to yield a linear polymer. Aniline retarded the polymerization and no polymer was formed in the presence of triethylamine. These inhibitory effects were explained on the basis of complex formation of 9-BBN with amines. This polymerization is discussed in terms of a non-radical mechanism. © of SCI.

Synthesis and photochemical behavior of 2-(N-acridonyl)ethyl methacrylate and its polymer

A polymerizable photosensitizer, 2-(N-acridonyl)ethyl methacrylate (AEMA), containing both aromatic ketone and aromatic tertiary amine moieties in the same molecule, was prepared by reaction of N-hydroxyethyl acridone (HEA) and methacryloyl chloride in the presence of triethylamine (TEA). HEA was obtained by reaction of acridone with ethylene carbonate. The photochemical behavior including photoinitiation and fluorescence properties of AEMA and its polymer P(AEMA) were studied. It was found that the photoinitiation efficiency of monomeric AEMA is lower than that of its polymer for the photopolymerization of acrylonitrile (AN) in DMF. By the kinetic study and the analysis of recorded electron spin resonance spectra of the photoinitiation systems of AEMA or AEMA-dimethylaminoethyl methacrylate (DMAEMA) trapped by 2-methyl-2-nitritopropane (MNP), the mechanism is deduced to be similar to that of the benzophenone-TEA system. The recorded fluorescence spectra show that AEMA and P(AEMA) possess a strong fluorescence emission peak at 410 and 439 nm, respectively. The concentration self-quenching effect was observed with maximum intensities at a concentration of 8.6 X 10 -5 mol/L in DMF for both AEMA and P(AEMA). Even though AEMA has a tertiary amino group and an electron-deficient acrylic double bond in the same molecule, it did not display structural self-quenching effect as we reported previously. This may be due to the two benzene rings in acridone that lessen the electron-donating ability of the N atom. The fluorescence quenching of AEMA and P(AEMA) by electron-donating and electron-accepting compounds was also investigated.

REACTIONS PARTICULIERES DE CYANO ALKYLE SULFURES APPLICATION A L'OBTENTION DE DERIVES ACRYLIQUES

Abstract The reactivity of Ph-SH with acrylic compounds permits a protection of the acrylic double bond and reaction on the protected product. In some cases (cyano alkyl acrylic compounds) a specific reaction can be observed. So action of KCN on PhS-(CH2)2-COO-(CH2)aCl [n = 2,3] gives NC-(CH2)2-COO-(CH2)a SPh [the expected compound (PhS-(CH2)2-COO-(CH2)aCN) was not isolated]. We involve a sulfonium ion as intermediate for this ‘abnormal’ reaction. When n = 6 the normal protection/deprotection reaction occurs.

Vinyl monomers bearing chromophore moieties and their polymers. II. Fluorescence and initiation behavior ofN-(4-N′,N′-dimethylaminophenyl)maleimide and its polymer

A maleimide bearing electron-donating chromophore, N-(4-N′,N′-dimethylaminophenyl)-maleimide (DMAPMI) was synthesized from N, N-dimethylaminoaniline and maleic anhydride in the presence of acetic anhydride and sodium acetate. DMAPMI can be easily copolymerized with vinyl acetate (VAc). In addition, it can be easily homopolymerized by UV light irradiation or by using AIBN or BPO as an initiator. The fluorescence spectra of DMAPMI and its polymer or copolymer were recorded and compared at the same chromophore concentrations. It was observed that the fluorescence emission intensity of DMAPMI was much lower than those of its polymers. This may be due to the occurrence of intermolecular charge transfer interaction between the electron-donating dimethylaminophenyl moiety and acrylic electron-accepting carbon-carbon double bond in the monomer. The model compound, N-(4-N′, N′-dimethylaminophenyl)succinimide (DMAPSI), which has no carbon-carbon double bond, displayed the same fluorescence behavior as DMAPMI polymers. The fluorescence of DMAPMI polymers and DMAPSI can be quenched by electron-deficient compounds such as AN, TCNE, MMA, etc. All these results supported the above conclusion. This is another example of the “fluorescence structural self-quenching effect” termed by us previously and demonstrates again that this phenomenon is not an accidental but a general one for acrylic monomers bearing electron-donating chromophores. Study of the initiation behavior of DMAPMI and its polymer showed that they could initiate the photopolymerization of AN, by combination with BPO, they could also initiate the thermopolymerization of vinyl monomers such as MMA. © 1996 John Wiley & Sons, Inc.

Synthesis, characterization and polymerization of dendrimers with methacrylic end groups

AbstractDendritic methacrylic crosslinking agents were synthesized by modification of amino functional poly(propyleneimine) dendrimers. On the basis of model reactions, several experimental methods for the introduction of methacrylate end groups were evaluated. In case of the Michael reaction of 2‐(acryloyloxy)ethyl methacrylate (1) the amino‐end groups of the dendrimers of the second, the fourth or the fifth generation add exclusively onto the acrylic double bonds of 1 forming methacrylic end groups in the modified dendrimers. The quantitative and uniform conversion could be proved by NMR spectroscopy. Analogous dendrimer modifications were carried out with mixtures of 1 and other acrylates. The dendrimeric methacrylates of different generations were polymerized in solution and bulk at 80°C with 2.2′‐azoisobutyronitrile as initiator. The polymerization enthalpy of the dendrimeric methacrylates was determined by differential scanning calorimetry and shows that the polymerization of approximately every double bond takes place. The polymerization of methacrylic dendrimers yields crosslinked polymers with glass transition temperatures near or below room temperature.

A gravimetric and Spectroscopic Study on the Photoinduced Radical Co-polymerisation of Methyl and Allyl Methacrylates: Kinetic and Structural Properties.

The photoinduced radical co-polymerisation of methyl and allyl methacrylates has been monitored by gravimetric analysis, Fourier Transform infra-red (FTIR) and FT nmr spectroscopy using a range of different photofragmenting and hydrogen atom abstracting type initiators. Using both visible and UV light sources the rates of photo-co-polymerisation were found to follow similar trends in both bulk and solution phase. Furthermore, unlike thermal polymerisation wherecrosslinking can occur through the allyl group, only the acrylate double bonds undergo reaction to produce a copolymer. GPC analysis showed that the homopolymers produced had narrower polydispersities than those of the copolymers while the photofragmenting type photoinitiators produced polymers with lower number average molecular mass than those produced via a hydrogen atom abstracting type. The latter is associated with marked differences in the degree of self-termination by initiator fragments. Structural analysis of the homo and copolymers by 1H FT nmr showed that photoinduced polymerisation produce polymers with a greater degree of stereoregularity than those obtained by conventional thermal radical initiation. Thus, the initiating process appears to play a major role in controlling the orientation of propagating chains.

Recent developments in photoinitiators

A new photoinitiator, bis(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentylphosphine oxide (1), has been developed for industrial applications. The absorption of this bisacylphosphine oxide (BAPO) compound in the near UV-Vis range is significantly higher than that of hitherto known photoinitiators for UV curing. Investigation of the photochemistry of 1 revealed the efficient formation of four radicals, which can all initiate polymerization. Since the photoreaction is accompanied by the destruction of the chromophore responsible for absorption in the near UV-Vis, photobleaching of the long wavelength absorption is observed and the photoinitiator does not impart yellowing in the cured lacquer. Studies using FTIR and RTIR techniques showed that these features result in a higher conversion of acrylic double bonds than obtained with other photoinitiators in formulations containing a high loading of rutile type titanium dioxide pigments. These findings were confirmed by application tests in different white pigmented coatings. Further, the new photoinitiator allows the fast curing of thick pigmented layers, which makes it suitable for use in pigmented furniture coating. This new class of high performance photoinitiators is expected to promote the development of UV curable white coatings of high opacity and other applications where light in the near UV-Vis range is essential for curing. A liquid containing 25 parts of the BAPO photoinitiator 1 and 75 parts of 2-hydroxy-2-methyl-l-phenyl-propan-l-one ( 2) is an excellent technical and economical solution for most applications. ▪

New Phosphanyl-Substituted Titanium and Zirconium Alkoxide Precursors for Sol-Gel Processing

Zirconium and titanium alkoxide derivatives with phosphanyl substituents were synthesized by reaction of the alkoxides with 2-acrylamido-2-methyl-propane sulfonic acid followed by addition of HPPh{sub 2} to the acrylic double bond. Alternatively, the phosphinated sulfonic acid was prepared first and then reacted with the alkoxides. The second route is preferred because of the milder reaction conditions, shorter reaction times and avoidance of byproducts. The bifunctional organic ligand is bonded to the titanium or zirconium atom via the sulfonate group, while the PR{sub 2} group is available for further reactions such as the coordination of metal compounds.