It was the document that started a revolution and ended up bringing Europe to the brink of war. Ukraine's association agreement with the European Union, a mainly economic document setting up a free trade area that nevertheless has political and strategic ramifications, will finally be signed on Friday.

Along with Georgia and Moldova, two other post-Soviet countries keen to move out of Moscow's orbit, Kiev will sign the deal with Brussels to establish a free-trade area and introduce a raft of measures designed to synchronise economies with EU nations, as well as improve rule of law and human rights.

It does not guarantee eventual EU membership, but is seen both in the countries themselves and in Moscow as a major step westwards.

The European commission president, José Manuel Barroso, said this week that the agreements were of "huge strategic importance", coming as they do amid unrest in eastern Ukraine.

"The agreements, the most ambitious negotiated so far by the European Union, aim to deepen political and economic relations with the EU," said Barroso. "We will need to remain active and vigilant regarding our eastern neighbourhood, in particular after the signature of the association agreements where our responsibility increases and not diminishes."

Ukraine's president, Petro Poroshenko, will travel to Brussels on Friday to sign the agreement. "This is what we have fought for over recent months and years," he said. "This work will be as difficult and responsible, but I am confident that we will do it very well."

The signing comes four months after Viktor Yanukovych was ousted by a popular revolt that started when he performed a U-turn over signing the agreement last November, citing the need for further negotiations with Russia.

Russia has expended huge energy and pressure in its attempts to coerce Ukraine into joining its rival Eurasian Union, but is now resigned to losing its western neighbour to Europe, even if unrest in the east continues to give Moscow a voice in Ukrainian affairs.

The Kremlin is also unhappy at Moldova's decision to look westwards, and many in the country fear that destabilisation in the Moscow-backed Transdniestr breakaway region could follow.

The loss of Ukraine has dealt a serious blow to the Eurasian Union project. Ever since the Soviet Union collapsed there has been talk of recreating a new alliance among its states that would have more weight than the loose Commonwealth of Independent States grouping that succeeded it.

After several years of planning, on 1 January next year the Eurasian Union will finally come into being, linking Russia, Belarus and Kazakhstan in a more formalised version of the customs union between the trio that has been in force for several years already.

Moscow has spent years putting pressure on Ukraine to join the union. In 2012 the top Russian banker Andrei Kostin told Ukrainian politicians that the EU deal was an "arranged marriage", while Russia offered the country "real love". Last year the Kremlin's Ukraine adviser Sergei Glazyev warned the country of social unrest and possible secession of pro-Russian regions if it signed the agreement. In the end, Yanukovych backed down at the last minute, but Glazyev's predictions came true as the Kremlin annexed Crimea.

Resigned to the loss of the rest of Ukraine, the three-state alliance will attempt to draw in new members among other post-Soviet states and beyond. At the signing ceremony in Astana last month, the Russian president, Vladimir Putin, was gushing about the potential for the union.

"We are forming a major centre of economic development that will bring together 170 million people," he said, pointing out that between them the three countries had 20% of the world's gas and 15% of its oil. "Wherever I go and whomever I meet, everyone wants to know how to establish relations with the new Eurasian Union."

Recent events in Ukraine, and the ensuing western sanctions, have led the Kremlin to give more importance than before to the political aspect of the Eurasian Union. Combined with a recent huge gas deal with China, the union is part of a pivot away from the west and towards the east, where business dealings come without accompanying lectures on human rights or geopolitics.

"From now on there are no illusions about the EU and the US," says Robert Shlegel, an MP from Putin's United Russia party and a member of the parliamentary committee on Eurasian integration. "We sell Europe resources, and we know that as soon as they can substitute them with resources from somewhere else, they will, so it is necessary for us to seek new partners."

For the other members of the grouping, however, there has been unease over recent events in Ukraine. Alexander Lukashenko, the authoritarian president of Belarus, has criticised Russia's grab of Crimea, while Kazakhstan, with its large population of ethnic Russians, has become uneasy about the newfound zeal with which Moscow is "protecting the rights of ethnic Russians" in neighbouring countries.

Both the Belarusians and the Kazakhs have been keen to emphasise the economic nature of the union. Other former Soviet countries, especially Armenia, Kyrgyzstan and Tajikistan, have expressed interest in joining the union for the potential economic benefits but are wary of the potential political aspect.

"There is a feeling that for the Russians it is first and foremost a political union, whereas Kazakh officials have gone out of their way to emphasise that it is an economic grouping," said Dosym Satpaev, an analyst based in Almaty. More political elements of early drafts of the union treaty, including coordination of foreign policy and common passports, were removed after pressure from the Kazakhs, he said.

There was another risk in joining an alliance made up mainly of autocracies, said Satpayev. "Authoritarian regimes are harder to integrate. At the point when any of the leaders end up leaving office, there is no guarantee that their successors will want to pursue the same foreign policy."

With the Kazakh president, Nursultan Nazarbayev, well into his 70s and no obvious successor on the scene, this is more than just a rhetorical question. "If a future government of Kazakhstan or other countries involved wanted to leave the union, would Moscow be happy to let them go or would they apply pressure and move along the 'Ukrainian scenario'. That's another question that worries some people," Satpayev said.